MungoP,
Jobs are generally NOT advertised through country of registration. It soon becomes entertaining when you are taken on to fly an M-reg, to find out it's now G-reg because the owner is going to charter it out. (And perhaps gain some tax advantages
)
If you are EU based however, as of April 2015, you will need a current EASA licence to go with your FAA one flying an N-reg based in the EU. However the Channel Islands are non-EU! (Ideal if based there)
Word of mouth is probably best job wise, which may be a little unhelpful to you. CI jobs don't appear very frequently.
There are a selection of registrations within the CI, of which a max of 50% are G-reg, because they are chartered out!
Best of luck.
SKP