Hi, the possible solution to this has problem has been answered in another forum here, have a look at that first, it may help regarding hot water issues. It will be the diverter valve, a few issues can stop it working as described in that forum. Hope that helps, if you are a competent DIYer it will cost no more than £50 (but shop around on line - some diverters for this model retail for around £200) the after market ones from italy are cheaper. If you want to strip the diverter valve and put in a new diaphragm it can be fixed for less than a fiver!
Steve, January 2010