diaphragm help - erm, it seems to be rotating...

[CoffeeCrisis]

So I have a new diaphragm and I haven't used one before

and you have to place it with the 'removal dome' at the front behind the pubic bone and then check that you can feel the cervix behind it which I can

but when I come to take it out the whole thing seems to have rotated and the removal dome is somewhere round the side

and it's hard to get out but I don't mind so long as it still works

does anyone else have, you know, roaming issues

I have used diaphrams with success in the past but not had any rotation like you describe. It sounds like it is not fitting properly. I'd seek advice from your GP and use condoms short term.
Did you have it fitted by a nurse or have you just bought it and started using it without guidance from a FP clinic?
Where I live (UK) NHS GPs and FP clinics don't recognise or support diaphrams as contraceptive methods. This is one reason why I stopped using them. Also spermicidal gel became impossible to get. Good luck