Most job agencies simply want to get as many c.v's as possible on their files, so that they can improve their chances of of having the 'ideal' candidate available as soon as an employer contacts them. They always make 'encouraging noises' to potential employees but, in reality, most c.v.'s simply sit in a filing cabinet for a month or two, and then get binned.
The vast majority of employment agencies now advertise their vacancies through Job Centre Plus so, instead of looking at dozens of different agency website, it's a lot easier to look at the JCP website. (It will also include hundreds of jobs, in your area, which never get referred to the commercial agencies).
The JCP website allows you to specify the type(s) of work you're looking for but it's probably easier to select 'All' and see what's on offer. More importantly, it's a national database, so you can enter your postcode, together with the distance that you're prepared to travel, to see all jobs within whatever radius you decide is reasonable. For your first search, you can ask for all jobs listed within the last week (or fortnight). Thereafter, you can check back daily and request only jobs listed within the past 24 hours.
A few minutes spent browsing the site will give you a good indication of what's currently available in your area:
http://www.jobcentreplus.gov.uk/Internet/setLo cale.do?country=GB&language=en&page=/initialis e.do
Chris