the thing is is that they know if you got the contract that you would more than likely have to employ people to do that particular work, they then let you do that and after x amount of months turn around an cut the payments, then your up the creek without a paddle as you either
a. take it on the chin and make a loss
b. tell your lad his wages are bein cut
c. cut your losses and tell tesco to sod off
Also when do you actually clean these stores? the one by me is open 24 hours and i dont think the shop or customers would be happy with me cleaning wfp as there walking inside