Chappie has done the trick. Firm and brown this morning!!! Put out the flags. He isnt eating it as quickly as he was yesterday though. I think its the old "I like a new tin best, dont like that one thats been in the fridge". Our other dog was like this with the other half can.

I need to find some charts now that will give me a clue as to how much a day he needs. It says on the back 5kg dog 1 can a day. He 1.7kg so Im giving half a tin a day divided by 4, but what I will be doing is checking one of those charts which says how many calories a pup needs a day at particular age/weight, and working it out from there (I hope). Unless anyone else knows.