Hi all, just learning DIY and doing my first room. Going mostly good but got to the window wall and realised there is already metal angle beads in. Can't find any explanations on what to do? I've tried to just go up to the edge but made a bit of a mess around the bottom as when polishing I realised the coat was thicker at the bottom of the window and quite feathered further up. will have to tidy up later and maybe easifill but wondering what I could have done differently as have another bedroom to do in a couple weeks. Assuming it would make a right mess to try and get old ones out etc?