I've landed several times at Lasham in powered SEP aircraft, admittedly for a purpose but certainly not on gliding business. Parham, Wormingford, Challock, Upwood and Rattlesden as well. Some have planning issues or movement limits for power aircraft. I personally think it's more like: "you power pilots can't possibly be as good as us glider pilots, so be a good chap and buzz off"
If you want to land at a gliding airfield that 'bans' power, just lob in unannounced, land exactly where you want, start making phone calls and when challenged, tell them you ran out of ideas and "landed out'. Works for gliders at the private strip I fly from which only accepts any aircraft by invitation...
As lasham pilot can I explain why we discourage power without prior permission. We have a very large site and are trying to make everything within the perimeter track landable and currently have part of the site recently seeded.
Normal gliding operations will have the control bus on the main runway. The winch will be placed on the grass with the cables towed out on the grass parralel to the runway. Club aerotows use the main runway starting level with the bus. Trial flights start from outside the club house. We thus have 3 launchpoints coordinated by radio.
Circuits can be both right and left handed landing on the grass on the appropriate side of the runway without crossing the centre line.
We also have ATC a Boing maintenance organisation on site who have jets, helicopters and twins arriving and departing.
Overhead joins are forbidden as we have steel winch cables to over 2000ft. During the summer the site can get very busy with movement peaks of over 200/hr. Total movements 59,000pa busier than most regional airports.
This set up is very different to a normal power airfield. We are not better just different.
As an example we had a visiting pilot last year who insisted on doing 5 mile 3 degree approaches. After 4 go rounds because gliders cut in front of him he finaly wised up and flew the same tighter steeper circuit.