Hi Keith
It didn't have tape over the hole but it had plastic over the pickguard which I didn't notice for awhile!
So I suppose I don't really know if there's a spring in it except it doesn't actually fall out so I'm guessing it's ok?
I tightened the trem bar today to see how it felt and it stayed in position nicely but felt a bit awkward when I was playing so I think I'll have to get more confident in my playing and then adjust my technique to having it in a firmer position.
Thanks for your help.
Best wishes
Rosemary