Mark Oliver Plumbing & Heating - Expert Oil Boiler Services & Installations

Had a leaking cold water tank in loft. Mark responded very quickly both in coming out initially but also finding time to replace really quickly. Mark was punctual, professional and left everything spotless. Would highly recommend. Thanks Mark

Mark came to service my oil boiler & found a couple of things that were not quite right. I’d been told previously by another engineer that the boiler was not able to be repaired, so to be told he could fix it was a great relief. He went to great lengths to get the correct gasket & came back promptly to fit it & finish the service. His service is second to none, so if you have an oil fired boiler, Mark should be your first call for servicing or repairs.

Annual service of Grant Oil boiler. Conscientious, efficient, friendly and clean . Been using for heating and plumbing for 15 years.

We’ve had a new Grant Vortex boiler supplied and fitted by Mark this week and as usual he did a fabulous job, very professional, clean and tidy job. Would have no hesitation in recommending his services. 10 out of 10

Mark has been our go to boiler man for over nine years now. During which time he has annually serviced, fixed and installed a new boiler. Also handled an issue with oil feed and other bits and pieces along the way. At the end of the day he’s reliable and reacts when you have an issue. I’m happy to recommend him.

Back in January 2026 I discovered I had a leak on the watermain under my drive. Southern water were no help at all so I got advice from a plumber who suggested laying a whole new main and quoted me for the work. However, they would not commit to a start date and all the time I was losing a lot of water. I then looked at Southern Water's list of approved plumbers (WaterSafe Register), picked out local plumber Mark Oliver, and left a message with his AI assistant. Then things started to happen. Mark came back to me straight away and quoted me less than the original plumber. He got on with laying the new main promptly. Unfortunately we had to wait 4 weeks for Southern Water to inspect the trench and further week to connect the supply which was yesterday 27 April 2026. Yes, over 3 months of disrupted water supply and serious loss of water. Until Mark Oliver became involved the situation was causing me a great deal of stress but Mark took control and made things happen. Mark demonstrated empathy for my situation and had a 'can do' no nonsense approach. A good sense of humour too! Would definitely recommend.

We recently had a new oil boiler installed at our home in Botley and we couldn’t be happier. Mark was professional, punctual, and very tidy, explaining everything clearly during the installation. The boiler works perfectly, and the follow-up service was excellent. Highly recommend for anyone looking for reliable heating solutions! We would use the services of Mark Oliver Plumbing & Heating again in a heartbeat!

I recently had my water heater replaced by Mark Oliver Plumbing and Heating. I was a little concerned about the water heater replacement, a big old ugly tank to a new water heater, all work was professional and the old parts were taken away so I was not left to take the tank to the tip, Mark was happy to clean and tidy when he was finished, Mark also replaced the shelf’s in the cupboard which was a big bonus for me. I would recommend Mark for any plumbing needs in the future.

Really personable guy, who gave clear communication about what was going on with our boiler and how he was going to fix it. It was a difficult job but he managed to fix it and were nice and warm again! Thank you Mark!

When I found Mark just over a year ago my view/opinion was at an all time low for oil boiler technicians. Having had bad to abominable service for the five previous years. To say nothing of haemorrhaging money! I first called Mark over a year ago to do a service, he was a dedicated Grant technician recommended by Grants. I had never seen such a thorough service carried out. This year I developed a leak. Could not identify where it was coming from. I called Mark, I didn’t have to wait two weeks, he moved his diary around to accomodate. He replaced a valve. Next day strong Kerosene fumes. Mark attended promptly. This went on for several days, including New Year’s Day. Mark attended next day and completely changed, valve, reduced end of copper feed pipe and replaced cable. Success. We still don’t know specifically where the leak was coming from. It’s day three now no more fumes, boiler running well. I thank Mark for his dedication to dealing with this. He didn’t suggest, as previous had, oh you need a new burner, costing £800 installed. For the number of attendances Mark has made to resolve this issue demonstrates to me Mark will be my boiler technician of choice going forward. Not only a good technician, but a very polite, professional, friendly person, a scarcity today. Thankyou Mark.

Would highly recommend Mark - he has regularly serviced our boiler and is always very reliable. He also goes above the standard service, recently our boiler had failed but it was due to the fuel running out. He helped me over the phone to restart the boiler and was more than happy to help and get it going. Turning down a call out charge to ensure we got our heating back online so we had heating for our young baby.

Mark has been looking after my boiler for some years now. He’s friendly efficient and reliable and has kept my home warm and snug. Thank you Mark.

Excellent service. The heating engineer was very knowledgeable, quickly diagnosing our boiler issue. Really appreciated the honest advice and quality service - would highly recommend.

Thank you so much to Mark for replacing my water cylinder! Quick, efficient and professional service. Highly recommended.

My external oil boiler failed completely at the end of October 2025. I was very lucky to find Mark Oliver who managed to schedule me in and a few weeks later we had a new boiler up and running. He has provided an excellent service at a reasonable cost.

My family have used Mark for a number of years, across several different properties, and have always found him to be hardworking, professional and reliable. Should things go wrong, Mark goes out of his way to help and has come out to fix boiler issues promptly in the past. I cannot rate him highly enough!

Called for a quote He put the phone down on me after he presumed I didn’t note down the phone number for the office When i called back after he had been rude he made an excuse of bad service

This guy is rude! And cut me up on the round about and slammed his brakes. I was in a red mercedes clearly can see unless colour blind.

When our 25 year old oil boiler became unrepairable, Mark attended promptly to survey our system and advise on boiler replacement. Within a few days he returned as arranged and replaced boiler and ancillary equipment. He worked methodically ,with no damage or disruption ,and soon all work was completed in a professional manner ,and to within the very competitive quote he had given.

Splendid service, arrived on time to repair my oil fired boiler. Very professional and excellent quality. My oil boiler is working like new again now. Will definitely use this company again