Whirlbird, had the same myself,
Firsy, go see your GP, he knows you best and probably knows a decent cardiologist. If you're really lucky you may get the first one on the NHS.
For class 2 med you have to undergo the three tests you mentioned, these are fairly routine provided your heart is structurally sound.
For class 1 med you need to undergo the three tests twice at least 12months apart then periodically thereafter.
Watch out for CAAs record keeping, its ****, ie:? obtain hard copies of everything and take the name of anybody you communicate with at LGW.
Hope this helps,
AO