Metal Micky glad I was able to be of assistance just confirm There is a requirement for a separation between hot and cold water ultimately to ensure no non potable water enters the water distribution system the thought is if cold water can force its way from cold to hot then in certain...
Two questions to clarify
If you were to not fit a hose to the kitchen tap but just let it run cold to waste for the same time would the over flow then leak?
Am I right in assuming your heating hot water system has a storage hot water cylinder in an airing cupboard?
Or have you a combi boiler...