I have a single bike trailer that's not for sale, but could be - but I'm up in York. Galvanized, great condition, quite small too, but I've had a 999R on it OK.
i use the Erde' Pm300 but the newer PM310 is a little better. good for storage as they can be stood on the end etc and also very light to pick up.
There is one for sale on trackdayriders forum. http://www.trackdayriders.co.uk/tdr/forum/erde-single-bike-trailer_topic70939.html
I've been looking for truck parts that could help me haul my bike. I searched google for some suggestions and found Kendon. Seems good and easy to store. I need a storable trailer for lugging my bikes to the shop.