Piece of cake. It's behind the bulkhead on the passenger side, accessible from under the bonnet.
Open the bonnet, remove the rubber strip that runs along the first bulkhead, and then ease out the flat plastic panel that covers the battery, wiper motor, brake reservoir etc.
On the right hand side of the battery, you'll see a another moulded cover, about nine inches wide & six inches deep, held in place by two clips. It also has a small piece of piping running across the top of it. Release the piping, unclip the panel & tease it out of its location. Hey presto! One pollen filter!
If you're thinking of replacing it, try cleaning it first, save yourself £26, as per the following:
.
How to clean a pollen filter
An added bonus is that the fresh smell of Bold Automatic now wafts through the car, LOL!