You can pick up brand new ones on eBay for £25 including delivery. I fitted ones of these yesterday and is a good fit.
http://www.ebay.co.uk/itm/Ford-Puma-1-7i-16v-125bhp-Water-Pump-05-97-05-02-/330640255643?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4cfbb1ea9b" onclick="window.open(this.href);return false;
I wouldn't think it would be worth picking up a secondhand unit for the price of a new one but that is just my opinion on it.