Cardiff only checks to see if the right subjects have been taken, and Lancaster only requires AAB predictions. Both offers would be AAA though. If your second choice would be something related to medicine (eg. Biomed, biochem etc.) you could apply to the med schools open to you without much harming other applications. If you could get interviews (good GCSEs for Cardiff and good BMAT for Lancaster) you'd have a pretty substantial chance of getting offers.
That being said, if you don't think there's much chance of getting in with your current qualifications and predictions for BMAT and A-level, it may be better to just focus on a different course and save yourself the stress. Medicine is not the only good career choice.