Nigel
You, as you say work in London. Sorry but this is a totally different world to what most people in this country work in. I work in Teesside, North East England. The world you inhabit is a fantasy world compared to me. Prices per sq foot you can achieve, is probably, if I'm lucky, can achieve per sq yard.
London as as stated in today's Telegraph is in a 'bubble', the real economic world does not exist, in this bubble, even allowing for 'all your competition'. It is nothing and repeat nothing, when compared to people who are willing to to work a 10 hour day for £25.00. If you have no access to benefits, this feeds your family, plus credits. As I say another world. A world you seem oblivious to.