We had an large landing window with six panes of patterned coloured glass. When we had replacement windows (double glazing pvc) for the back of the house, we had the large landing window done, but it has not been successful because as soon as the coloured panes were put into the new pvc frame we noticed that some of the colours became patchy. We contacted the company concerned and they say there is nothing wrong, but I feel that there is, is there an expert out there that can give us some advise. It was a very expensive job but we are not satisfied.