You guys are incredibly helpful - this is the type of detailed info that makes this forum so valuable.

As for LCY, does every Green Park train stop at Canning Town? And does every DLR train departing Canning Town stop at LCY? And is the transfer from tube to DLR fairly idiot-proof: are there signs clearly pointing the way? Just trying to determine how I can screw things up!

This doesn't mean that LHR via Hex is off the table - the hint to take a cab to Praed/Hilton is brilliant