Hello, does anybody know how to get the top off this ideal standard basin mixer tap? If you have a look at the pictures? It has a handle which is unscrewed inside there is a Allen key screw which can be removed but there doesn’t appear to be any way to get the actual top off the top that’s what I want to achieve. Two reasons. It has a leak coming from the top which I wanted to investigate and also the screw that I unscrewed which attaches the handle is somewhere inside it so I can’t put the, handle back on, any help will be appreciated