Looks like you've blown something, has the controller, (or anything), worked since you took the pump apart? That pump has nothing to do with the hot water side of your system. All the pump does is shove hot water from the boiler around the radiators when the CH is switched on.
Secondly, the heat sink rad in the toilet, is this getting hot since you had no hot water? The HW circuit relies on gravity to circulate, if it is blocked or air locked, circulation will not happen, hence you've no hot water.
Can you just check their isn't a motorised valve hidden down the side of the cylinder or anywhere else, to rule out a C plan system please.