If you have a broken or missing pollen filter frame then don't despair. A new design of pollen / cabin filter was created in 2012 that takes the place of both the old filter and frame.
Essentially CU and CUK 26 010 supercedes CU and CUK 2545 and you no longer use the black rectangular flimsy frame that surrounds the pollen filter element.
I should also clarify that filter airflow direction arrows should always point towards the centre of the vehicle. That is air flows from left to right sitting inside a RHD car.
Here is a link to MANN documentation explaining the change. Although it doesn't mention the A2 specifically the fact is that CU and CUK 2545 were the original correct part numbers for A2 pollen filters; so the change also applies to A2s.