If there is anyone near or not so near to Depford who has a cordless angle grinder and could lend if for a bit quite urgently - a mate of mine broke a key in his kryptonite and now has his bike stuck to a fence in Depford.
Alternatively, do you know what other ways there are to get through the lock? Does a hacksaw do anything, with a dozen spare blades?
believe it or not in victoria many moons ago my lock failed, I walked over to the fire station, had a quick chat, we all jumped in the fire engine and they cut it off with their bolt cutters. (not a d-lock though). If you don't ask you don't get.
I once saw a guy sawing away at a lock outside Liverpool Street station. I jokingly asked him if he was stealing it. He gave me a baleful look and said that he had already spent an hour at the nick across the road trying to prove that the bike was his and that I was about the eleventh person to approach him. At that exact moment an anal looking commuter came along and accused us BOTH of being bicycle thieves.
I once got my kryptonite stuck round my waist, I lost the key and had to ask nicely the firemen in shaftsbury to remove the thing.
they couldnt use the jaws but used a hacksaw, one fireman holding me from behind and one either side pulling the lock to expose the inner cable and one with a hack saw. It looked like a rape scene from certain angles, i wasnt complaining - they cut me lock off.