An area or place dominated by brash, loutish behaviour or unsavory characters ie Chavs.
JC - do you want to meet at the pub down the road
CH - No thanks, it's got a chavmosphere
DP - there's a strong chavmosphere in here, should we go somewhere else?
FWD - It's all the chavs in here
Trying to pick up at the end of an evening out at a bar, club, party, etc usually at close.
Can also happen as you make your way home.
Like the show, the challenge is to find something/someone within the what's leftover (the scrap).
Ashley: Everyone is dancing, no chance of picking up in here.
Jo: Not long until close, we can play scrapheap challenge outside.