If it's emergency repairs probably nothing we can do but you could try calling City of London Noise Nuisance: 020 7606 3030. More phone numbers are on the Estate office page http://www.goldenlaneestate.org/page/estate-office
That's outrageous... you probably haven't got the energy to but you should complain - there's got to be a code of conduct for late working.
It was Uk Power networks. I have a friend who phoned them but they didn't say if it was to do with COLPAI or not but I'm pretty sure it was. I've emailed them but all a bit late now.