Think I read somewhere that all new builds in LOS have to be earthed.
My house was built in 2007 too, the builders were dumbfounded at my earthed 3 pin socket request, I did get through in the end, even an earth at light fittings.
But, the biggest, dumbest thing they did, which I only found out by accident, and at a different house of a friend on an estate was, the A/C & showers do not go through the consumer unit, they are earthed, but there is nothing to trip.
I replaced all the wall switches to them with Haco trip switches, had to do it with the live......????