OK problem solved, thanks for the tips. My initial adjustment obviously wasn't quite right so after further adjustment it all seems to be back in place.

I had already done the hose mod for the air-con drain so glad this seems to have resolved it for the moment.

As an FYI, if you're non-technical like me and have this problem in the future, the non-technical version of 'adjustment' is wiggling it around on the two bolts. Dead easy to do and nothing to be scared of