Mate
Ive just replaced mine using the good old Just Kampers website.
V easy to replace BUT........the tank on my camper hadnt been used for a while (3 years + I would say) so there was a bit of gunk in the bottom.

So I flushed it through using some powder chemical stuff and where I could, scrubed the inside of the tank. This loosened more debris and also led to the cleaning of the pipe that leads to the sink. I had to remove the tap at one stage because it too had become clogged.
BUT...............after all that (a couple of hours) I got a good pumping rate and clean water running through the tap.
Job done , well chuffed with myself

.
Let me know if you want anything else on this subject, Im not at all mechanically or elecrically minded but do have a degree of common sense
Good luck