Is it wise to give up non-driving, full time employment to do the above?
Some contracts are for around 4 months but I am concerned there may be a lack of opportunities when this period runs out.
Any suggestions would be apprecaited
Speed Freak:
Is it wise to give up non-driving, full time employment to do the above?
IMO - NO 
Sorry to disagree with ROG but in my experience of agencies I’d say yes.
If you prove you can fill a contract for them reliably then they will certainly give you more work once its over, more than often they will keep you on there for longer, or have you go straight onto another contract.
It all boils down to Do YOU want to do the driving work? if thats your aim then yes, go for it!
Alex
Thanks for the wisdom guys.
On of these days I will get passed the ‘oh, you don’t have any experience!’ hurdle 
Scarab:
Sorry to disagree with ROG …
Never be sorry to disagree - everyone is entitled to an opinion - we just happen to differ on ours
contracts like that are rare with my agency. its normally day to day but as i work full time hours with an agency and have done for all but 10 months over the last 6 years i would say that you can go to and agency and earn a full time wage. there are quiet times but you make up for that by working 11 days out of 14 when its busy. plus working nights and weekends earns a premium rate which helps. the first few months will be spent proving your worth but once you have shown that you are reliable they will be offering you more work than you want with the added bonus of taking days off when you want