I would imagine that the crew would have committed to EGCC if possible. Therefore using the div fuel+contingency to hold. From the situation you describe I would imagine the cew had decided not to commit because a landing was not assured at EGCC (for whatever reason). The crew would then have had enough fuel to divert elsewhere (not EGGP). Thus leaving only the contingency fuel+any extra, for holding at Dayne.
Assuming no extra fuel is loaded then that just leaves contingency for holding at Dayne. BA have a statistical policy on contingency fuel. In SH BA uses 99%. In other words, 99% of the arrivals from Dayne on that service from the last 3 months hold for less than 10mins. So 3 times a year that service will hold for longer than the 2 holds/10mins you've quoted RP45.
If the crew were unwilling to commit to a landing at EGCC, contingency fuel may be all they would have for holding at EGCC, assuming no fuel was gained en-route (poor routing etc..). Just because EGPP was shut doesn't justify carrying more fuel to EGCC other than for reasons of diverting to a more distant airfield. So the div fuel would be increased on the flight plan and contingency would remain the same.
Trip+Statistical contingency+div+res+taxi+(extras)= Total fuel.
In other words it sounds like the crew were following sops correctly and doing a good job of keeping atc informed. This does NOT sound like poor form at all!