Well OK BOAC,
You mention an EAT. If you have that, then the time at which you leave the holding pattern loses its significance, since you burn fuel till touchdown in either case.
The method of calculating fuel burned after leaving the hold only works if the approach is standard, so I reckon that you have hit the nail on the head with the EAT, which works wherever you fly.
You also mention the approach being draggy, if taken on the S tour. I agree that it was in your recent experience but it doesn't have to be. When I see how much traffic the LGW controllers move, compared to say NCE with two runways, I reckon they have it "down" pretty well most of the time.
(Thanks for the 20Mi.note.)