Why thankyou chaps, in answer to several sub questions;
firstly getting a glass to hold water upside down over the adhesive, on the upcurve of the bath, could tricky

, best keep that idea for winning fivers down you local,

but thanks for the input nevertheless

, and secondly, yes I have had to clean up after plasterers, messy buggers that they are

, plaster is an entirely different entity, so what may work with plaster (vigorous rubbing) may not necessarily work with adhesive. (easy with the vigerous rubbing boys, you know what happens if you rub too hard)
The only real concern I have is the chap who's bathroom it is, is "an angry short guy" who has had to deal with the plasterer putting the corner of his trowel through his newly installed false ceiling, so his patience is a little thin already. So I just wanted to make absolutely sure of no damage.
Once again the lobby offers superb ideas that wouldnt be out of place at a science fair, I am humbled. (in short, cheers chaps)