Mark, strange that you should pick "The Axe" in Shoreditch as the basis for London beer prices
Hmmm, I suppose it depends upon the venue, but can think of a few venues near me that charge well over the 3:50 mark. Our local den of inequity, charges 4:50 for tart fuel (Smirnoff Ice), despite being full of Essex Girls of illrepute.
I suppose the best solution is:
1) Buy a couple of bottles of Grey Goose / Absolute Vanilla / Smirnoff Black Label from Duty Free and drink before you go out
2) Don't drink at all.
Anyway, aside from the minor issue of drink prices, flying into Torp is reasonable in comparison, and certainly handy for those near Stansted.