i have a mark two barefoot london, only just available( i had to order it direct from germany). it has foam panels underneath to give a proper channel and decent wither clearance. i am using it on a 14.1 new forest pony who is very round and flat and so far she has gone beautifully in it and i am very pleased. my ri said "what the hell is that" when i turned out for my lesson but had to concede by the end that she had gone much better in it than in my treed saddle. i have also previously used a trekker talent on her but wasn't happy with the lack of wither clearance it gave. overall i am very impressed with the quality and design of the new london, it is such a relief to be able to saddle up without her pulling evil faces at me!! if you anticipate problems with the saddle slipping forwards you could alwalys try a crupper. make sure if you intend to buy one that it is the new model though as they are not yet being advertised over here. hope this helps, annabel