In reply to Sam Beaton:
There are a lot of chancers out there, I had a lot of roof work done last year and the approach I found repeatedly was, we’ll bodge it up for you for a couple of grand, then come back in 2 or 3 years and replace the whole thing for you.
Eventually found a wee firm - Dumfries based, so probly too far away for you - called Topseal, not much more than a one man show, but Andy conserved everything he could, re-sealed my 50 year old tiles, replaced some rotten timbers and installed dry liner and new gutters. He discussed every stage of the job, took photos, and showed the rotten bits he was taking out. I think the challenge is in finding someone with that kind of approach.