<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by Psychiatrist:
well .... i might go 6 hours early then .....</font>

Really you'll get bored unless you can camp out in the MB Spa all day.
As much as BAA are trying to turn LHR into a shopping mall with an airport connected onto it, you'll be quite bored. You could always take a trip to the Terraces lounge by Gate 1 and go to the Sanctuary upstairs, you could get some sleep there