If you've got a few hours to wait at LGW, and you're flying economy class, it might be worth having a word with the check in staff, and asking nicely if you can get into the Virgin lounge. They've let me in a couple of times when I've had a 4 hour wait between flights.
If not, you can sometimes pay to go in (at the entrance). I think it's £25. Once you've had a nice breakfast, a few coffees and other refreshments, it's not bad value at all.