When our conservatory was finished, alongside the final bill there was a feedback questionnaire asking if the installers had followed certain procedures (they had, where appropriate) and asking how satisfied we were and if we would recommend the firm to friends and neighbours. The gist of what we put was that the builders, installers and electricians were courteous, efficient and seemed to do a good job, but we were unhappy with the lack of communication from the company (there were big delays and getting information about what was going on was like getting blood from a stone) and the fact that they tried to change the agreed payment terms towards the end (after a very wet summer, I suspect cashflow was an issue for them). As a result, we said, we couldn't really recommend them.
Well, that was a couple of months back and we didn't hear back until a couple of days ago when <3 received a phonecall, apologising for our dissatisfaction and saying that if we could pop into the shop, they had a hamper of goodies for us. So yesterday we went by after work and now have a rather nice M&S hamper containing lots of lovely consumables, including cake and pudding to supplement our home-made ones, in case we get more visitors than expected.
While we still probably won't be recommending the firm, this has left us with a much better feeling about the experience. Hopefully the goodwill gift is a sign that they have taken our criticisms on board, but if not, it's not a problem: we no longer need windows or conservatories, and we have a great supply of sweet (and other) stuff for the holiday.