As someone who's actually worked in the UK for quite a while, I see a mixture of "they all do that, sir" and a couple of things you'll need to correct.
First, there is pretty much no way I have found to get a decent IT job in the UK that doesn't involve a recruitment agency. As I mentioned in a couple of comments already, 90%+ of the hiring is done via agencies, both in the permanent market and even more importantly, the contractor market (because for the latter, the company wants to keep you at arm's length due to IR35 etc). So unfortunately, you'll most likely have to deal with agencies even if you don't want to.
As to recruitment agencies not getting back to you, that was pretty normal for the last 3-4 years. They get inundated with CVs for pretty much any position at the moment as the IT job market still isn't that great (from what I can tell from here, haven't worked in the UK for a year). I know this is frustrating but I've been in similarly perverse situations where I was contacted by recruiters for jobs (usually ones I didn't want) and couldn't get an answer out of the same companies for jobs I was actually interested in.
Also, your CV being in LaTeX is a really, really, really bad idea IME. Most recruiters' tech knowledge doesn't go much past switching on their computers in the morning and using Word. And that's OK, they're not techies, their job is to find a couple of candidates. Giving them anything else but word will ensure you instant access to their bit bucket and not much else. Redo your resume in Word format and you should get better responses. I would also suggest that you don't put out your resume in PDF format as someone suggested; most recruiters will insist on removing your contact info from your CV before they pass it on to their clients and they usually can't or won't do that with PDF (or anything but Word).
What worked for me in the UK was doing the following:
- Find a couple of agencies (yes, I mean two or three) that constantly appear to have jobs in your chosen field. It's not unknown for agencies to post phantom jobs to get your CV into their database but with a bit of practise you can usually figure out which ones are real and which ones aren't. Once you've got a couple of agencies you're happy to work with and they're happy to work with you, you will get better responses. I've had most luck with a fairly small agency that was only working in the field I was in (Finance IT); they were very good at finding me contracts so I didn't really need to bother with other agencies.
- The scatter gun approach doesn't necessarily work. TBH, with you making it unnecessarily hard for the recruiters due to the LaTeX CV, I'm not surprised that you haven't got much in the way of responses. That's normal, even with a Word CV and you'll have to probably contact even more agencies and be more patient if you're using this approach. You can expect something like a 1-2% return rate, much as if you were doing some sort of direct mailing advertising, which in a sense you are.
- Put your CV up on a site like Jobserve. I never used any other service (OK, I have my CV on Stackoverflow careers but that didn't work too well for me) but Jobserve worked rather well. I still get recruiters contacting me who found my CV on there even after I took it down about six months ago.
- Make sure you've got an appropriate list of buzzwords on your CV that can be found with a simple 'grep'. I usually put those in the skills list. The reason for these being present is to make it easy for recruiters to run a search on the CVs they have in their database and come up with a match. If you don't partake in their buzzword bingo, you're probably not going to get a call.