Stay well cat flap blocker, how do I remove it?

[MollyQueenOfSocks]

Have attached a picture! Moved in to a property with a cat flap but one side is blocked by a plastic "staywell" cat flap blocker. The actual cat flap is underneath (pic from the other side) it but having tried to pull it away or locate screws I can't see a way to get the bloody thing off so the cats can use it!

It looks upside down and like it has been painted in!

Can you pull the upside down bit down? They normally slot in but pull up. You might need to take a knife to the edges to score the paint.

it's a guillotine type action isn't it? Slides in and down or up .