Just succeeded in putting new filter in, 95% seems to go in easily enough after bending the sodding thing to gat back in (and out!).
The other 5% was a push at the end (seemed a bit crushed up, especially at top by about 10mm), hopefully it will be fine after a few rattling miles..
Not the easiest one to get in and I am not sure after all this bending and pushing if it isn't crushed up. I guess I will find out if I have to clean the dust every day