Something I always like and something I like to do is take the trouble to go and speak to people face to face. Very easy to send out a batch of cv's and letters and most firms receive loads. If you can deliver them by hand, look the part, and introduce yourself. Takes a lot of effort but I am much more likely to give a positive response. It may be that the person you speak to can't help, but they may know someone etc.
Also, don't be afraid to stop and ask if you see a van etc and ALWAYS follow up any cv's you send/hand out. Don't expect anyone to come beating your door down. You don't have to pester people but you can start to build relationships and network.
You sound like a really positive and pro-active guy. With the way things are at the minute it will take some time and effort but if you keep at it I reckon you'll find something.
Every "No" is one person closer the the "Yes" you're looking for.
Good luck, Mate.
Thanks for the advice and encouragement!
Where possible i will do all the things you have said. Difficult at the moment as i am still in full time work and i think that im holding back a bit as i feel that only being able to do weekends will put a lot of people off giving me a chance but as you say it will be good for networking. Will be hard work but i'm actually looking forward to it and it excites because i'm going to do everything i possibly can and will be good to see how things develop. Definitely going to do things in person where i can and get myself noticed.