Hi Woodster,
Yep, we ended up doing something similar. They kept messing us about, we ended up with 4 seperate quotes, the first time they got the square footage wrong but the address right, the second had the right address but the square footage had gone down etc etc - and the price seemed to go up each time. We ended up losing faith in them eventually and have now gone with someone else (i should also mention the quote went up by about £600 from thier original estimate for no apparent reason)