I have had a few peices of feedback from various production companies and been suggested to find an agent to help me progress. I have read on other threads that finding an agent is not a good idea at this stage. So I am now confused! Apart from The Writers and Artists yearbook, is there anywhere I can find a list of agents who may be interested?
The writers and arists yearbook is the best place I would think.
I'd send to everone who deals with sitcoms.
Maybe someone like Tim can advise you better.
"We suggest you find an agent" can mean "Your work is so wonderful we'd hate to be accused of underpaying you for it".
It can also mean "Please don't send any more of your work unless it's already been read and approved by someone who knows what we're looking for".
If you'd like to post an example of your writing in the Critique section, the responses may indicate what 'Find an agent' means in your case. 
Cheers for your help so far. Many thanks