Builders and Roofers

[Fred]

The answer rather depends on whether you'd prefer good or cheap! I'm afraid they are frequently mutually exclusive.
The best advice is to get three quotes so you can compare them. See how you get on with the artisan concerned and talk to some previous customers.

That is very good advice.

Unfortunately there have been cases of the British ripping off the British. That does not mean all British are the same and there are some very good British builders and roofers out there, but I have seen a few cases where people have been ripped off by people that pretend to know what they're doing but in truth know nothing and just make it up as they go along.

I would say use registered builders only, yes you may pay a bit more but in the long run it could save you money and a lot of heartache. Get three Devis (Quotes) on headed paper with the builders name and conditions of payment from three companies preferably that have been recommended to you or ones that are happy to show you some work they have done.  

Most of all be very very careful.

Sorry I can't recommend anyone myself as I've not used any apart from a local French window fitter who can highly recommend.