thanks for all your replies! Ruti (the diabetic one) is already off the evil biscuits and I do test him at home anyway, he is pretty stable and has been for over 2 years now. Apart from the quite frquent bouts of cystitis (like the one this morning yuk!) he is fine! it just would be nice to chat and swap tips with someone else who has a diabetic cat!
Does anyone else give their cat apple cider vinegar? Ruti has it twice a day and although it seems to clear his cystitis up very quickly, it doesnt keep it at bay!!! anyone got any suggestions?????

thanks

quick update! found cystaid and so far we have not had an episode of cystitis for over a month now, thats the longest dry run for neearly a year :-)