There must be different British laws vs. US around calculation of APR. The annual fee and interest assumptions appear to both be included.
"50.1% APR. We assume you use your card for a purchase of £1,200 at the commencement of this agreement and repay it together with applicable interest and charges by 12 equal monthly instalments over the period of one year at the standard interest rate for purchases set out in section 3 "The interest rates which apply to the credit agreement" and does not take into account any promotional rate that we may apply or any change in the interest rate. Using this agreement for transfers and transactions other than card purchases may result in a higher APR."