BA SH has a new "Flight Planning System" as of 10 days ago (Cirrus - as mentioned above).
For Airbus, work on ~10-15mins less holding time than previous before diversion / PAN into LHR...
The previous system had a little fat - the new one, no fat, and seems to actually burn a bit more then Flt Plan (& FMGS for that matter).
Once holding gets much >20mins, and if people continue to take Flt Plan fuel, we are going to see more of these diversions... I am sure there will (have to) be some "tweaking" of the system soon...
NoD