Point taken -- I've been trying to conduct as much of this by email as possible in order to have a written record, and intend to get testimony from my current employers that they really need me to stay this extra time really a lot, and basically cover as many bases as I can imagine. Being pretty familiar with the political situation around immigration these days thanks to Radio 4, I figure there is no such thing as too paranoid when it comes to this stuff, so it's reassuring(?) to get confirmation that this is not a crazy thing to do.