Hi Guys I to have a Series 2 with the plastic brace, I have found a way to get the filters out without cutting the plastic brace. all you need to do is remove the 3 screws and 1 spring clip on the Black box the filters are in and lever it open just enough to drop the bottom filter which unlocks the top filter, you can then slid it out, it's a little fiddly and you need to bend it a little but it can be done
Regards Phill