I have done this cant find a wet pipe, but there can be a puddle under header tank on floor

gunk in the oil filler cap can be caused by a number of things not allways headgasket failer, 1) low oil level and short journeys creating moister hence the gunk as it mixes with oil and short stop start journeys can cause this too, check for staining around neck off resevoir for dried coolant as this could be the seal gone and leaking under pressure paul

Thanks Paul i'll have a look for that later and look to see if there is any dried coolant

Water coming from water pump, looked under engine and can see discoloured water marks, how easy to change water pump.
Local motor factor quotes £26 for new one

not sure on how hard it is to change but i would suggest replacing the timing belt and tensioners whilst in there and the alternator belt as these need to come of to change pump would save you money on a second garage bill and give you peace of mind that the timing belt is done as if it goes it becomes a engine rebuild paul

Cheers Paul I'll get a quote from a garage i use Paul