Thanks all. I know Jersey are very helpful and that it would probably be easy enough, because otherwise you could find yourself in a situation where you are in a Radar Control environment inside Jersey zone (and hence have to comply with ATC headings etc) but rapidly approaching Rennes TMA with no clearance! Ok if you have box 2 to call them on, but I suspected that you would probably be handed off - just nice to hear other's experiences.
ta