The bit circled in yellow

I've read that you remove the two screws and then it should lift upwards and off. Like hell it does. I've even been giving it a good twatting with a rubber mallet but it won't budge even slightly. Am I missing something? Do you have to swing it outwards and then lift? It has a rubber strip running along the top of it - does that have to come off first? I've doused it in WD40 so it runs behind in the pathetic hope it might help.
It's doing me head in!!!!!!!!!!!!!
