Cheers for that. Very informative.
I've just sent a few emails and made some calls in order to secure a 'host' at Lee. My main issue is as you can imagine a lot of IFR training and therefore the bulk of my experience is largely within airways and heavily focused on flying (aysmmetric) approaches etc etc.
So a 200nm 'straight' off airways route is definately not something I claim to have much experience in.

BUT, you have to start somewhere I guess.
Having read that link I posted there seems to be no need to flightplan at all on such a flight and if I choose to go IFR in uncontrolled airspace and off airways, there appears to be no issue beside pilot qualifications.
It's been too long since I did any GA in the UK but where better to start than straight into the deep-end.