In my experience, 350 was the low end. When recruiting, we couldn't get any decent people for under 400 (and I mean decent; 350 got us a Web front end developer who didn't know CSS). 400-450 did get us amazingly knowledgeable people, though, so that extra 50 was a small price to pay.
Out of curiosity were you recruiting developers directly or going via a headhunter or agency? £350 that I see a lot is what's offered from headhunter emails filling my inbox everyday. They take a large margin for themselves as a finders fee.
Yeah, it was a recruiter. They probably did inflate the prices a lot, although I think they took some days' wages as a fee or something. I can't be sure.
