Personally every car ive had that runs water pump directly off the cambelt ive replaced without question, you find that tension changes between the new and old belt can cause a pump to fail,

i had this on a 98 rover 414 :)shrug: what was i thinking), cambelt changed, pump looked perfect, only to find it fail two weeks later, a waterpump change is near on the same operation as changing a cambelt, so expect to get charged twice labour wise, 100 quid labour, or 24 quid for a new waterpump and 3 mins to fit whilst doing the cambelt, i know what i'd choose, change it without question,

preventative maintainance