thanks guys!  I tried giving it to him on the side of his mouth today and that worked heaps better - only had some spillage yay 
 
Have tried beginning of feed as well but he's waiting so long for a feed these days (his choice not mine!) that he's ravenous by the time he's asking for it and screams if I try the gaviscon first... 
Did you find giving them Gaviscon disrutped their sleep patterns?  We had a really good routine down that since starting Gaviscon has totally changed - just wondering if it was the medication or just a phase...