Originally Posted by ReelChief
With your point, about the left luggage being adjacent to the arrivals lounge, does that imply that one does not have to go out of the transit area to check in the luggage.
It is landside, so you will have to clear immigration/customs before retrieving it. You turn right after exiting through customs, walk towards the Arrivals Lounge, and it is to the left of the long corridor towards the lounge (and I believe near some car rental desks and the lifts to the Tube station).