Are you making this up as you go along?
It is other countries eg US that won't accept UK blood. The UK is fairly self sufficient for whole blood but I think still imports some blood products such as Plasma and platelets.
Despite efforts there is no test for CJD. That is the problem. CJD is an extremely complex and controversial topic and has nothing to do with punting.
No, I'm getting it from the NHS website I linked to earlier.
"Blood transfusions
In the UK, there have been 4 cases where variant CJD has been transmitted by blood transfusion.
In each case, the person received a blood transfusion from a donor who later developed variant CJD.
Three of the 4 recipients went on to develop variant CJD, while the fourth recipient died before developing variant CJD but was found to be infected following a post-mortem examination.
It's not certain whether the blood transfusion was the cause of the infection, as those involved could have contracted variant CJD through dietary sources.
Nevertheless, steps were taken to minimise the risk of the blood supply becoming contaminated.
These steps include:
not allowing people potentially at risk from CJD to donate blood, tissue or organs (including eggs and sperm for fertility treatments)
not accepting donations from people who have received a blood transfusion in the UK since 1980
removing white blood cells, which may carry the greatest risk of transmitting CJD, from all blood used for transfusions"
So it looks like nobody who has had a blood transfusion since 1980 is allowed to donate.
So they import blood when they need to ensure a good stock level of different types.