Hi Samantha
The problem is an internal fault with the shower that keeps the water on for 10 seconds to remove residual heat from the heating element
The solution i have found is to
1/ Turn fully on the nearist cold tap to the shower ( normally the bath tap ot sink tap)
2/ Turn the shower to its cold position
3/ Try operating the on off button leaving about 20 seconds for the water flow to stop ( you may have to try this a couple of times )
Hopefully it will save you from having to dash around the house in a bath towl dripping water everywhere , to find the bath tap
The only other solution is a new shower
Tony W, January 2008