Thanks for taking the time to have a read Stu, much appreciated, will have a good play with it this weekend (pending the exhaust being repaired).

Ordered a new pump and a set of 071C's from you yesterday (for £11 it's worth a shot), promptly arrived this morning, spot on. I've factored in changing the pump anyway as it's 20 years old so it must be getting tired by now!

The pump voltage readings barely altered from idle to 5k+ RPM (thats driving it, not stationary).