Rob
How many plates CAN you read, and under the proper lighting!!
second it is not advisable to 'learn' the plates, the plates are presented to you in a random order to prevent this, if the AME feels that there is cheating going on, its not going to achieve anything!!
the cad test on utube is a sample of the actual test, but its best to try at either city, or glasgow caledonian eye clinic, as they can also offer the holmes wright lantern as well, and that test is still valid providing you follow the CAA protocals for it.
believe me, ive been there, i score a pass to the test standards but not to the CAA standard, and didn't pass the cad test as it went on far to long, they are supposed to use the fast screening cad to start with, and the long version test deeper into the red/green area that was found to the weak!! feel free to PM me.