I am going to replace a standard rad. in my bathroom with a towel rad.At present the pipes come out of the floor vertically,I am going to re-route them so that they come out of the wall horizontally.I have good access to the pipes and I am going to drain down the system to do the necessary alterations.Once drained down I was considering using isolating valves on the pipework under the floor so I can refill the system and carry out the alterations in my own time.The questions I have is it ok to leave isolating valves under the floor,which type of valve is suitable to use on C/H system and should they be full bore.