There are not so many about as there used to be and most of the firms that want out workers are based in Scotland and want the traditional Arans etc.I used to do out work arans years ago but most of the firms have disappeared.The only thing I can suggest is that you contact the British Knitting Guild .
http://www.knitting-and-crochet-guild.org.uk/
who may be able to point you in the right direction. Failing that if you want to make a couple of bob ..hand knitted items especially childrens jumpers etc sell well on Ebay.
Happy knitting !