Hi Blair, and welcome.
As Brian rightly states, I use a 4' x 3' trailer to move Harvey's wee car about.
There are some pictures of it on the forum somewhere, I think they are in the 'General Discussion' section, under 'Trailer Modifications'.
The front board of the box has been made removable, and I' ve added a shallow frame to the front of the trailer, above the draw-bar, for the front wheels of the car to rest in, similar to a 'Spectacle' towing lift, I then hold the Toylander in place with small ratchet straps, which secure around the frame at the front, and into 2" holes drilled into the floor of the trailer, to hold the rear end in place.
Walter on the other hand modified a Motorcycle trailer, which he had. He added two small rails for the Toylander, and straps it down with ratchet straps as I do.
I would suggest a trailer that will be 'Dual Purpose' would be the best option, like a small box trailer. So that you can use it for duties such as rubbish removal etc; and Toylander haulage when the need arises.
You might have problems if you need to transport both your cars though, as some local authorities have regulations on the size of trailers allowed onto waste sites, so it might be worth checking beforehand.
I hope your idea of a Central Scottish meeting bears fruit, as Brian says, you might just have 'shaken the bushes' with the suggestion.

Keep Busy,
Regards,
Mark.