I totally get not wanting to go through clearing - the thought of spending 3-5 years at somewhere I hadn't even visited before really wasn't appealing.
None of my placements were YINI - I applied for a quite few of those and although they say that they become available throughout the year, most seem to start around now and be given to people who applied a year in advance. Only fair I suppose, but a bit of a pain.
I applied to lots of big energy companies and automotive manufacturers, as well as a few smaller random ones - there are lots here in the midlands. I basically looked at all of the companies that sponsored a science fair I once did, and had to google for ages to get email and postal addresses. If I got stuck I phoned up and asked - usually I was given the email address for HR. At the same time I was applying for jobs in all of the local supermarkets - I'm kinda glad I got rejected by these otherwise this year could have gone very differently!
Make sure you mention any relevent skills you have - I think I got one of my placements because I said in my covering letter that I could program and use Excel.
A friend also took an unplanned gap year, and she worked as a science technician at school like some other people have mentioned (covering 3 months of maternity leave), then a different automotive company from me, and finally at a cafe to save up some more money.
Good luck - really hope it goes well for you!