is it part of the same series as Meerkat Madness? there seem to be a few different animal in different books. Are you thinking of 'The Koala Brothers' TheSurgeonsMate? that was my first thought but I think the books are for younger children.
A fairly recent series about three (i think) pandas, or koalas, or some sort of bear, i think. they are from australia and they have adventures. (i think) the author is a man and I think he usually writes adult novels. I think maybe they fall down a hole and end up in the UK? I also think they are for 5-8 year olds. does this ring a bell? it's driving me crazy. I think there are two perhaps three books in the series. I used to have it in my cart at amazon to buy waiting until dd was old enough but i erased it by mistake. thanks so much