that one is odd. As I am not british (yet) it is hard to find some specifik thing on google (anyone typing shock absorbers will be shocked at the result).
Anyway, to cut the long thing short:
Garage where you can do your own DIY at your own pace. and if you F8K it up or get stuck there is a mechanic next to you just in case to push you in the right direction. Plus most of the tools that you will need....nirvana
If you have a house but no garage, or if you rent, or ...no garage. Where do you go to do your own bits? on the road, in the rain , hail, snow.
I did that for my gasket, my waist is hating me since then.
Here is something that I believe is of good value. I am not sure if it is the same people behind but seems reasonably priced.
One of them has a free WiFi which is a bonus as you can access realoem, bimmerforum, skype. Just do not forget your laptop....
As I have not read the advertisement caveats I will post the names you will have to google it:
pitstartgarage - london
selfservicecentre - j29 of m1
autopiaservicecentres - convenient for Manchester and Liverpool. Got special price for carclubs (irrespective of the number of the cars. Groop service anyone?)
thediygarage - coventry, close to M6
there was another one to south-south-west of Birmingham (the one with the WiFi but can'/t find it now. Should have bookmarked, I know.