visa exp=30 nov, is it ok if COA posted 31aug/receivd 1sept?

[vitalik]

hi
my visa expires on 30 of November 2006. if i send the COA application on 31 of August 2006 and the Home Office receives it on 1st of September would that be too late for it.

i know it is very silly to do that, we are on holiday and coming back on 31. i thought it would be ok since i thought that it is the date of the despatch not the receipt that matters but i now have doubts.

very many thanks
v