This is going to sound really dim, but how do I refit a K&N panel filter to my MY99 Uk car? The filter was originally on the car but removed at a service.

As well as the filter there are 2 bits of rubber - looks like these should go at the top and bottom (2 short sides) as the K&N filter is smaller that the OEM part, but putting them in the airbox first makes the gap too small for the K&N filter

It should be one of those "my granny can do it " easy jobs but I'm stuck!!

Any help much appreciated

Phil