To give some practical advice there are plenty of short strips around.
For anyone who has not done this before (and with a southern England) bias I would start by going to somewhere like Maypole. See how that goes, make careful note of how much of the strip you use and be very critical of where you touch down and what your actual landing roll is. Try it in carm conditions and with a reasonable cross wind - you are achieving much less by landing into a reasonable headwind, because the headwind might not always be present. If that goes OK maybe book a flight into Deanland which is a little shorter. After that try a few other farm strips particularly those on the side of a hill, or in valley, more challenging approaches etc. I think that is the sort of background experience you really need to go somewhere like Lundy. It is relatively easy to gain safely, and once gained gives you a far better idea about your own limits and the limits of your aircraft.