Well I have finally given in and bought a sand tray - I was reluctant as I didn't want a sandy house but sand is such a hit when we head down to the sandpit at the park that I just had to and £20 from Argos seemed cheap enough for lots of fun.
Its already a big hit, Chops has played with it loads and 5 of them were having great fun today - just got to crack the concept of keeping the sand on the decking!
I got my trusty tough tray out too so they could dig and make castles as well. Adding in other objects such as shells and lolly sticks to make it more interesting (and not all about plastic). Lots of birthday cakes were made!