Paxboy,
temperature is indeed critical for Concorde as higher temp = lower efficiency of the engines and therefore more fuel required for same distance.
Temperature is also watched carefully as parts of the airframe could start to melt after 130 degrees centigrade is reached. Therefore, on warmer days the mach number is reduced but as the speed of sound is greater in warmer air, there is little difference in flight time.
Finally, on the Westbound Concorde, speed indicated is usually around 1330-1360 mph on the Marilake, and height rarely exceeds 58K, so all in all you had a fairly normal flight.