I am attempting to clean my Gaggia Classic. Although I de-scale it regularly, it would appear that the shower holding plate needs removing for a good clean/replacement. The problem that I have is that although I can remove the shower screen and the two Allen bolts, I can not for the life of me get the holding plate off. I have tried:- Levering it off, but I can not see a rim to leaver off. Turning the whole thing upside down so that I could leave the plate to soak in de-scaling solution. Any ideas?