Lisa it sounds like you need to speak to Senna3's wife Trudi she works with problem teenagers at a special school/unit, she's been doing the job of a TA there for a few years now so knows a thing or two about getting through to them.

PM me your number or text it to me at 07956 271131 and I can pass it on to Trudi if you want

Try take away all treats, goodies etc.... this usually works without the swift slap! BUT you must be harsh. Whatever their favourite thing - Just ban it!! They soon sit up and listen!

Thanks so much guys :)
I am he most tolerant of people and am using all the strategies I can...they have yet to spot my bike pictures so that could be a reward in store and one I've used before. The positive behaviours ARE working albeit very slowly & I know (of old) that there is no quick fix. I just need some other strategies under my belt in case they get tired of these.
Apparently we're not allowed to use sweets coz they are seen as bribes! But thanks Glyn, I feel a sweetie jar emerging from my desk drawer!

I didn't think about Trudi, Kev Thanks for reminding me...I may bell her when I get really desperate.
Thanks guys...I know what I am doing already is gonna work eventually but rather than bang my head against a wall till it bleeds and cry myself to sleep with frustration I would pass it to you lot coz you always say such comforting things (even if it is "hit em with a baseball bat, Mav!)

Bit of light reading for you

http://www.dfes.gov.uk/behaviourimprovement/

PM to u