You don't need to take four A levels.
Try to remember the principle which each case represents, and as long as you can remember the shortened name of one of the parties, or the name of the ship if the case involves a ship, that's enough. For example, Hong Kong Fir Shipping Co Ltd v Kawasaki Kisen Kaisha Ltd can be remembered as Hong Kong Fur, and Central London Property Trust Ltd v High Trees House Ltd can be remembered as High Trees. It's much easier to remember The Hannah Blumenthal than Paal Wilson & Co. v. Partenreederei Hannah Blumenthal.
Criminal cases are harder to recall because Jones, Smith etc are not very memorable. Try to remember a salient fact (eg "the one about the bloke hitting someone with a chapati pan", the one about the stolen TVs" etc.)