I'll just add one thing to 2 Sheds' post in reply to A and C.
Duxford is FIS and as such cannot approve a land-after. The rules of the air apply and you cannot land on an occupied runway. I know it seem to lack common sense, when we are talking about spam cans on a long runway, but that's still the rule and there's no discretion.
Where there might be room for discussion, I suggest, is at what point does the runway become vacated? Air traffickers will clear an aircraft to land as soon as the preceding aircraft has vacated the physical runway and is till moving. You might take the view that the runway is infringed and therefore still occupied if the traffic has not yet passed the hold. I have never found a definitive reference to this question.
Alan.