For a start, I would investigate all of the refrigeration units in the building. If one (or more) has a bad compressor with stray current leakage problems or is habitually hard-starting, it would bump up power use a bit.
Are there other buildings attached to this one? Shut off circuits and see if any other persons try to find out why thier power went off!!It is possible someone accidently or deliberately tied into the pub's circuits.
If the increase is not too huge, I'd look into the possibility of a forgotten lamp(s)in some storage area being left on.
