Fuel filter was done some time around May - so plenty of miles have been covered since.
AMM - nope. Just popped the airbox top cover off, changed the filter & re-fitted.
Looks like we're hitting brick wall after brick wall. Guess it's time for the pros to have a look like you say. That could be a big money pit though. Change this item, £100, oh it didn't work, change that item, another £100, oh that didn't work either....