Surley, this Aussie fly boy's Flight Computer would ahve told hime was going to arrive a full 1 hour offslot, before he even left SIN.
Why didn't he just bide his time in the first Class lounge in the terminal building, rather than take off, knowing he was going to be a touch early?
Operating off-slot dosen't do the chap any favours, or the airline- do that enough times (as little as 4 (same flight, same day of the week)) and the right to land at LHR (Slot) will disappear like a gob of spit on a hot tin roof.
Not to mention these pilots who know there is Night Jet Restictions at LHR, but show up in the night anyway. The airport is allow a set number of movements per season, and the number is an absolute, no extensions, nothing.
Remember, you won't get your allowances, if your not allowed to fly to LHR anymore!