Thank you very much Rich912, I don't know how you found that, I have been looking for days. It still seems almost impossible, this morning I glued the cap direct onto the plastic popup thing below that acts like a spring, which is better than nothing but I did it lightly so will try again. This is a terrible assembly of tiny bits and very difficult to do but at least now armed with the pictures I can have a better attempt. Thanks again.
Wonderful, I am really happy now that I can do something about it - this is a great place to get help when you cannot get it from the manufacturer. You have done me a big favour IF I can fiddle with it, if I could be a little person about 10 cms high it would make it easier, but with the help from you and Rich I will get there. Thank you so much peshyxp.