The in-laws have just had a new bathroom installed. The WC and cistern arrived already assembled and when installed, there is a gap of around half an inch at the top of the cistern. They were told that this is how they arrive from the manufacturer and if they try to adjust the cistern, it may cause leaks. This is not a cheap WC from one of the sheds but a well known expensive manufacturer. I can't believe that a reputable bathroom fitter would think it is acceptable to leave it in this state but the inlaws don't want to make too much of a fuss.
When I installed my own bathroom several years ago, the cisten and WC arrived as separate parts and I had to join them in situ with no problems. There are a couple of pictures here.
http://92.236.100.215/bathroom/index.htmlOpinions please