HG, I too am trying to get a job in a school and i've been at it for 3 months now in a relatively quiet town without many school jobs. The thing is, every Mother around wants to be a TA. You get the perks of getting out early for your kids and not working any holidays and summer, so you can damn well bet that your application for TA is probably alongside many, many others.
I personally would rather do admin in a school than TA, but i've just applied for a TA position and I will be VERY interested to see if I get shortlisted for it. The person who just left that job is a fellow American friend of mine who was also a teacher like myself in the states, many many, many moons ago. So I dont get shortlisted, i'm going to do some serious self-hate.
I got a police disclosure when I was doing playgroup committee work and I didnt find it difficult at all.
Are there lots of teaching jobs in your area??? If you are having trouble finding ones in the paper, try your local council website. They usually have school vacancies listed there on TA positions that might not be advertised in the local paper...