Hello there,

Replaced both the pump and stat on mine last weekend.

Simple enough, so if you have done some before, no problem. Access is reasonable. I was nervous around the plastic stat housing, but with steady pressure on the spanner had no problems.
15mm socket on a breaker bar for the drive belt.
8mm socket to remove the pulley, then the mounting bolts.
Pump pliers to compress the hose clips if you still have the originals.
And assembly is the reverse of removal as they say in the Haynes manual!

Bought my parts from North East Jaguar Spares. On E bay and the net. Very helpful chap.

Had a poke around the exposed ports, but did not find any bits of the old impeller.

Dean