the qatari ruling family boasts a prestigious property portfolio in britain worth an estimated £ 740 million .
they have been quietly buying up trophy properties -- including the shard in london -- over the past eight years .
qatar 's constellation group bought a majority stake in company that owns claridge 's and the connaught last week .
family have spent £ 11.6 billion buying empire and sovereign wealth fund snapped up canary wharf for £ 2.6 billion .