A while ago I was about to undertake the replacement of my bay windows, I use a trade only based company to get upvc windows as I receive a much better price, however, I do not know how to measure them nor does the company I use offer a measuring service, therefore I am in limbo. Around december of last year I asked this same question and received an answer from a kind sole who gave me detailed written instruction along with a picture of a bay window. However, as Murphys Law dictates, now I have come to use this information and despite it being stored on my watched topics for forever and a day, it has mysteriously disapeared, I now cannot find this information anywhere on DIYnot and therefore would ask the kind individual or anybody else out there if they could give me some assistance, please - thank you