LTF
I think you`re figures are a little optimistic.For a start I believe that there are approx.1300 c/c at lgw not 3000 and being one of them I know that a fair few have the intention of striking.
You seem to have picked numbers and figures out of thin air ,even the vol.figures have not been confirmed.
I think 7000 to 10000 heads being available to work is wishful thinking.