Any hints for parts and technique to repair/replace a shower drain pump in a 36MKII?

I'm not deeply familiar with the 36.

I'm flying to the 36 to crew a transatlantic and will have a couple days before we depart.  Would like to repair it before if possible and if the repair doesn't happen we'll live fine without it.

Any hints on what replacement pump I'd want ot pre-order?

Any hints on replacing that pump - tricks or advice form those that have done it?

Thanks,
Andy