'95 Felicia LX Needs New Fuel Pump

We're pretty sure now that my Felicia needs a new fuel pump, so I've started a new thread to seek advice specifically on that.

It's a single point injection model & the sender unit/pump is a white plastic unit, mounted in the top of the fuel tank, under the rear seats.

Firstly, it seems there's also a pressure regulator in this same unit. Can we discount that as the problem?

Assuming it is definitely the pump, is it possible to acquire just the injector component & replace that, or should I be looking to get an entire sender unit?

Advice on either reputable second hand parts retailers, or links to either, non Skoda parts dealers &/or Skoda parts dealers appreciated.

If I'm looking to get just the injector, then postage won't be prohibitive. If I need to replace the entire sender unit, then nearest might be better.

I live between Oxford & London.

Thanks.