Waddington inform Humberside when R313 becomes active and then when it finally becomes inactive for the day. They are not told when individual slots are being flown, so there is a decent chance that you will be able to cross with Waddington even though H'side have it down as active.
That's exactly the sort of info I was looking for. Sounds like I should encourage Humberside to hand-over early to Waddington, or as niknak suggests a call on box 2.
Thanks all.