ICAO codes can make very little sense... esp here in UK. I find that if you try a little mnemonic for the less obvious ones they tend to stick. Some of the ones i have/had make absolutely no sense but it works... EGHD - High Definition - Plymouth. Don't ask how...
Practice for the stage 2 computer tests... a good nights sleep? you either have good reactions and spatial awareness or you don't really.
Best of luck though
