The T2 hangar is also not bunded and so in the event of a large jet A1 spill the fuel could not be contained and the fuel would quickly drain into the river Thames, the fact that there is an environmental monitoring station not a mile down the river can't help.
So the T2 hangar is limited to the storage of AVGAS aircraft ( presumably the avgas evaporates before causing environmental damage ) and one small turbine helicopter.