The fact that Stand 48 can't take a Boeing 747 unless it's parked at an angle and can push-back onto Taxiway Delta to face south for tug disengagement doesn't mean it's not available for use again if required.
Not sure if the service road that runs at the foot of stands 41 and 42 would preclude a 747 parking nose-in but maybe the airport company would temporarily close it under these circumstances?
The service road that runs around the east end of the new pier is due to be withdrawn from use shortly.
Stands 60 & 61 are both designed to take the Boeing 737-800 (the design type) and both were subjected to swept-path analyses during the design phase. One airline has submitted an objection to using Stand 60 because it claims that the spacing is too tight. However, this may change when the electronic docking and parking guidance system ('Safedock' see:
http://www.safegate.se/reference.asp) on stands 60 & 61 is up and running.
This system is in use extensively in the US, at other UK locations such as Birmingham and will be used for some of Heathrow's T5 stands.
