(replying to this zombie thread as it was something I looked at recently, so just for posterity)
A company that sells electric water pumps (EWP) for cars
Frequently Asked Questions - Davies Craig mentions a max power draw of around 120 W. So increase by an order of magnitude for a big aero engine and you should be comfortably within single digit kW.
The deal with an EWP is that it can be run independently of the engine RPM, whereas a traditional belt driven one must be sized for the worst case scenario which is high load low rpm. But for an aero engine particularly with a constant speed prop such a situation shouldn't occur so a relatively smaller belt driven pump should be fine.