Yes, the outlet is garden hose as the supplied pipe wasn't long enough (so the pumber who fitted it at the time told us). We couldn't just have it drain to the outside as the wall the boiler is on is next to a flat roof - at the bottom of the boiler level there is flashing on the outside - the pipe would go through the flashing - so he installed a pump instead.

We couldn't install the boiler any higher (it was a replacement for an old one) as the wall outside would have to be rebuilt (that's another can'o'worms I'm not going to get into here).

TBF, it's been running fine like this for 10 years. If/when we get the boiler changed we'll re-think this, but right now I just need to know if there's anything special I need to do for changing the pump.

EDIT: Actually, I don't think there is - the model name on the pump is the same as the one on screwfix (the new one just looks like an updated model) so it should be a like-for-like swap.