I have waited over a week to write this as I was honestly not sure what to write. After some deliberation however i decided to just stick to the facts.
The Good:
The price - Marks price was very good and only rose a little after a few complications (see later)
The Work - Was completed on the day and works
Timekeeping - Mark arrived on time
Overall - Mark is a polite chatty guy who very kindly showed me what the various parts of my CH and water system did (I'm a first time buyer). He arrived when he said he would and completed the work that I needed doing for near enough the price quoted.
The bad:
Preperation - Mark accepted the job without seeing it in person (only in photos I supplied after he said it was fine to not see it beforehand). As a result Mark arrived with no timber to construct a new base for my 50gal tank (replacing 25gal) and so spent a good hour trying to find a timber yard in the area and then going there and back. Even then he used a piece of ply that was already in my loft to make the base instead of supplying a new one.
Workmanship - To create a new base for my CH expansion tank Mark nailed several peices of timber using oversized nails into the joists instead of using screws. As a result the ceiling in the room below in the corner where the joists are has had lumps of plaster fall out which I need to fix. This wouldn't have happened if he had used screws and would probably have saved him a fair bit of time! In addition Mark left the loft insulation under my new 50gal tank which is contrary to just about every opinion and instruction I can find anywhere.
Time - Mark arrived at around 9 and didnt leave till nearly 3:30. I cant help thinking that 6 hours is a little long to install a new tank and move another.
After the install - After Mark had refilled my CH system I tried to get the boiler to fire up to make sure that I still had some heating. The boiler would turn on and the fan would spin but no flame would appear. Mark told me that he wouldnt leave me without hot water. After 30 minutes of looking at the manual and trying Mark handed me his invoice, got paid and left with some of his final words being "you'll have to get the guy in who moved it to have a look" (the boiler had been moved 2 days previously but was working before Mark arrived).
After just 30 minutes I had my CH working again, it turned out that there was lots of air in the system around the pump and flow sensors which is why the boiler wouldnt fire, once bled everything worked perfectly. I worked this out on my own despite having only the very basic knowledge of my system while Mark didn't think of it and is a fully qualified plumber!
Finally - In all honesty Mark is a nice guy who can be very helpful, but I wouldn't hire him again.