Thanks guys, I almost hope that the test comes back showing something so that we know what it is and can treat it. But the vet was talking about food intolerances and other stuff grrr! All I can do is wait, but it is weird as it seems to come and go, one minute he's as ok as possible for him and only going twice a day, and then it's like complete runs 10 times a day
he's a trooper though, he obviously doesn't want me to worry too much so he makes sure he climbs the curtains and causes general mayhem at least a few times a day so that I know he still feels good!!
Yuck that Mendozole stuff sounds awful, battery acid flavour eeeww! The one lucky thing is that Ru is extremely easy to pill, it goes... walk up to him, open his mouth, he meows, put pill in, shut mouth, he swallows. Good boy

But I think even he would object to battery acid flavour pills somehow.
The weird thing is that Java is absolutely fine. But we went through a dodgy belly kitten stage with her too, it's only in the past 4 months or so that she's suddenly gone perfect (she's now 1 year 3 months old). She was fine by the time we bought Ru home, but maybe she is still carrying something (we never tested her or anything as it was never THAT bad, like only once a day, just soft) that she's passed on to Ru? And he shows the symptoms but Java copes with them fine? Hmmm... oh I don't know!