Another thing to bear in mind that many lakes in the UK form part of the drinking water system. Not just man made reservoirs, the Teifi pools spring to mind but there are many others. There are very strict by laws in place about operating craft from these especially with prevention of transferring unwanted biological material into them. I seem to recall any boats used on these waterways had to go through a serious decontamination process if moved from one to another and as you have to carry out the process every time you remove the craft from the lake it does make aircraft operations some what impossible.