Annual increment is 2.5% in your anniversary month. Any increases due to a pay deal are on top of that.
Re allowances downroute, on the 'Bus I probably bring home (ie after looking after myself downroute) about £300 - £350/month. I haven't ever been sad enough to keep a record, so that might be an underestimate. Also, nb that I'm not a huge party animal, some of my more festive colleagues (!!) probably bring rather less than that home.