You will need to get her registered at a gp surgery you can do this straight away but they will need proof of id etc. Then she can see a gp who will be able to refer her. 

Noted and thanks. Anyone know if go straight to private hospital also ok?

Hi you can go privately without a GP referral using check 4 cancer they https://www.check4cancer.com/

Thank you for that link however it is important to point out that these are just diagnostic tests. [@Snoopybb28]‍ If the results are positive for cancer you would still need to be referred for treatment via your GP, so you will still need to register your mum with a GP in any case. You can't go direct to a private hospital without getting a referral but as Nnc247 has suggested you could go for diagnostic tests in the first instance