Original house contained cheap UPVC windows that were ill fitted and would not match the new windows in the two extensions. So the decision was made to fit new windows throughout with the original plan to go for alu-clad wooden, nut resorted to UPVC due to cost and worries on how some of the alu-clad windows were constructed.  Surprising how difficult it was to get quotes that were in an affordable category. Some companies needed numerous follow-up calls which was very frustrating in view of the