Hi Not an Expert on the GIS Job market byu any strecth but the UK really is all about experience and most specialist Jobs have there own Recruitment agencies or methods of advertising. I guess its because of how old the UK is that so many traditions and ways of doing things have become accepted..
Dont just look for the actual Job you do look into similar positions.
Im sure you googled i see there are quite a few GIS job sites about but of the one i looked at they were not interested in those who don't already have the right to work in the UK :(
But keep looking and contact the agencies, the adverts as we know for all jobs have more requirments than neccesary and of course want to discourage to many applicants from abroad for practical reasons (cost mainly). Often if someone is very good and they cant find someone of the calibre they will come round at least in my industry
