I’ve got a pretty poor credit rating (CCJ runs out next July) I have no mortgage or any credit so I’d it worth me getting a cc to improve and can I get one and not use it?
it wouldnt improve it if you got one and didnt use it. You need to demonstrate a history of paying it off for it to improve your credit score
If you can find one with no fee, then apply for one and put things on it and pay them off immediately
As I said on your previous thread, if you have a current CCJ you can pretty much wave bye-bye to a credit card. If you do get one it will be for a very small amount, say £200, and a very high interest rate. Until the CCJ is removed your rating will not improve.