Congratulations of entering the world of old oil leaking motorcycles!
I am in the USA so can't recommend a mechanic in you part of the UK. There are a number of people on this forum in the UK with all the knowledge to make your bike run as it should but it is up to them to offer their assistance.
Now the bad news, unless you have owned an old bike in the past and know how to wrench on them, a bike of 1940's vintage will not be a fun bike to own or ride without some mechanical skills. In the 80 years since your bike was made it has had a number of owners. Many of them will have no doubt bodged repairs on the bike back in the days when it was not an old and rare classic motorcycle but transportation that could be bought for very little money.
Motorcycles of this vintage also require a lot of maintenance compared to a modern bike if you don't want to be sitting on the side of the road with a dead bike and having no idea how to get it back running.
The best advice I can give you is to join some vintage bike club and become friends with those who know how to fix old bikes and are familiar with side valve BSA's. With a little knowledge learned from them you will have a big smile on you face as the M20 takes you down the road at a fast 40 MPH. And if something breaks, you will take out your tool roll and be able to fix it.
I speak from experience, I have know a number of people who thought it would be fun to buy a vintage motorcycle only to learn when it breaks down, they are on their own. Paying other people to fix you bike gets very expensive fast!
I hope nothing I have said will discourage you. A M20 is a nice bike to own and you be glad you have it.
Dave Plumb is not a million miles from you (Chester area) and runs his own motorcycle repair and engineering business. He's well versed with M20's. If you put his name in the search box, some posts by him will appear which contain his email address. Ron
Don't let anyone discourage you. Everyone on this forum has, at some stage, started from scratch with zero knowledge. The M series engines are an elegantly simple design that is made to be reliable and easy to repair (for the time). For me, learning how to rebuild and maintain my M20 is a big part of the attraction. There are some very knowledgeable people on this forum and they are generous with their advice.
You might try Peter Tipping. He's in Aintree, Liverpool so fairly near. Pete has run the family motorcycle business for many years, started by his father after the war (I think). Peter has built up his own collection of WW2 military motorcycles, all frame up restorations, so he knows his stuff. He's certainly helped me out more than once.
His phone number is 0151 526 1220, email billveloman@aol.com
Simon
I always encourage anyone starting out on old bikes to do as much as they can themselves....Start by sourcing the correct manual and parts list for the bike and begin to think about and acquire the tools you'll need....
It's true that in the early stages you will struggle and may well need some professional help to get it running correctly and keep it that way but that can be an expensive exercise if relied on totally and, ultimately, you'll never advance your own knowledge and experience...Not only that keeping it running yourself is a very rewarding experience as you get the hang of it...
Decades back when I was a (very) low paid apprentice I simply couldn't afford to take my bikes to a shop to be repaired so was forced along the 'learning curve'....Over time and via many mistakes etc. I'm told I've become an 'expert'...:laughing: ....
The fact is we all started off not knowing anything...When I bought my first bike (250 Matchless) the chap dropped it off at my house and as he left on the back of his mates BSA A10 he shouted back 'It's one down and three up'....I had absolutely no idea what he meant!!...:laughing: ...Ian
