Looks rather nifty mate. If you're not to happy about the feet having the boney segments still showing, you can use cotton wool balls and some latex to sculpt the tendon ridges visible on the pred feet you see. You can also sculpt the extra to this way too. Anyway enough of my rambling. Looks smashing.
In the UK HYDROCELL its distributed by KEYLINE builders merchants. Its Made by a company called FOSROC. Its not cheap tho 2m x 2m x 10mm costs £40 from Keyline. Its cheaper from FOSROC but their minimum order is £100.