Hi TT;
I haven't managed to get the time to get it sorted, but I've spoken to a few people about it and have all come up with the same idea, the selector valve in water pump. I've looked online for NEW part at around £10-£15, but might get one cheaper at scrap. It looks like a simple job but will take a while as you have to take the plastic off from under the windscreen, which also means taking the wipers off.

I suppose what you could do just to keep you going for now, is swap the two pipes so that the water goes to the front instead of the back.
I haven't looked to see if the valve is completely broken or just stuck, and can be loosened.
Let me know if you have any luck
Nik
