maybe there is a reason why they are grumpy tis london after all
All the friendly ATC are up in God's own county. Enjoying a slice of Wensleydale with their tea, a sure formula for happiness.
I use another London airfield a lot and there is a gumpy towermeister (locally, Yorkshirespeak, "TowerMester") there as well.
American ATC generally quite relaxed and casual ("watch out guys, there's a chopper commin' thru"). Australian, too quick to follow... Say again.