we have recently bought a swift challenger 470 se in lovely condition, we also got a new water pump with it which has worked fine up to last weekend, we can get water through the shower, but not the sink or wash basin in the bathroom, however if we slightly open one of the taps on the shower we do get water in the sink and wash basin, does anyone know why this is?? and what we can try next??? this happens weither we are running off mains or battery..........please help