London's old Tiger exhibit would have been perfectly suitable as holding space for two or three Lions, but of course we now know that this space will be used for over- night lodges.
Whilst I fully understand and often argue the point that zoos need money to survive, at the end of the day it's a balancing act. I'm presuming that, given recent changes, London is financially stable nowadays and would question whether the extra money gained from the lodges is really worth abandoning more animal enclosure space for? If they really, really need the lodges stick 'em on some unused non-animal space such as one of the lawns (I'm always frustrated that the large lawns remain empty in a zoo short of space).