You can buy them off ebay, if not try some of these sites for more feeders delivered in the UK,
http://www.livefoods.co.uk/
or http://www.livefoodsdirect.co.uk/
or http://www.livefoodsbypost.co.uk/index.asp
or https://www.petclubuk.com/view/menu.do?id=1
or...
My panther cham scratches on his door when he wants out, then usually he has his little wander around goes toilet in my room! and then walks back into his big mesh screen cage home cheeky cham!
It might b bcoz he may have more sperm plugs built up, or basically its his package. lol. Yea try the shower let it bounce off the wall n wait n see if he drinks. That reptoboost is some really good stuff try that too it helped my friends cham when he was ill n feeling poorly.