You seem to believe that in London and the South-East,
there are still large numbers of well paid jobs that will finance
a decent place to live. I don't believe that and I don't believe
if people in, say, Derbyshire came down to London, they would
find it financially feasible.

As you yourself have pointed out in the past, the main reason
large numbers of immigrants can take on low-paid jobs is
because many of them live fifteen to a house. That's tolerable
for a short period if the situation in your own country is worse
and if the exchange rate means that you will be able within a
couple of years to save what in your own country is a fortune.