jwf - sounds like fun. It great to be able to read up on other's experiences here and 'fly' the route with them.
And got a prompt reply saying they hadn't received a flight plan
Did they mean a flight plan, or that you hadn't booked out? I never filed a plan during my training. I did have to book out at Leeds though: Type & Reg, POB, Land away or local, duration, vfr, routing out of the zone, captain's name. It is preferable to do this over the phone rather than the radio - as you found out ;-)
What type do you fly? I'm thinking about the point you made regarding 2 stages of flap and wonder why you chose to do this - I'm used to PA28 where 3 stages are used for landing.