Like Brewnog i got my offer from Loogabarooga very quickly, in fact my 1st. They contacted me by writing but I don't think E-Mail had been invented then :-/
It really depends on so many factors, How clear cut you are, How many other candidates are being processed, Where your name comes in the alphabet, Even whether you went to the open day. I got unconditionals from Loogabarooga and Cranfield, but my oh crap option of Bath I got turned down for, probably because I didn't go for the interview, although I didn't go for an Interview at Looga either and they were 1st back.
The only thing you can do is sit back and see what comes through the post, fretting is not going to change the result.