OK that is all good and useful information, thank you.
Further to this, the client's contract stipulates that after 6 months they can hire a contractor without penalty, would the fact that this contradicts my restriction clause make it nullified or are they not related legally?
If I give 1 month's notice now, then wait 8 weeks, I would lose 8 week's income and we would be at my 6 month point anyway so that option isn't really viable.
The agency have repeatedly been paying me 'late'. I submit time sheets and an invoice on a Monday and get paid on Wednesday. Legally speaking they aren't late because they included a 7 day leeway period after invoice, but in reality it makes it very difficult for me not being able to predict when I will be paid, which is a primary motivator for wanting to go direct.
Secondary is the high margin they make on my day rate, which given they did little more than an introduction is not justifiable.
Specific to the restriction clause in my contract would you say it was enforceable based on your experience?