Can buy the swing up type from anywhere, Supercheap, BCF, most caravan shops, though the swing up job, unless you can fit it inside the drawbar will foul a WDH set up and isn't suited to bolt on, bolt off.
You do need the clamp to hold a normal one on but they can be welded to a plate which you could U bolt to a rail.
I had quite a look at who jockey wheels were on the market and thought about the "XO 500 series" jockey wheels which are quite tough but are quite heavy too and would have added to my A-frame weight worries, so gave it a miss.
I didn't need to get any extra brackets or anything, the boss jockey wheel just fits into the existing jockey wheel clamp on the A-frame
I am heading out tomorrow for 1 night to test the diesel heater and a few other things (check measurements for WDH to determine if standard shank will be suitable, see if stone guard on A-frame will be hit by my car when full locking the car left/right) so will take a few photos
Just be aware there’s been a few serious failures of swing away jockey wheels on heavy vans and trailers there really only good for light ball weights. As above the bos jockey wheel does a good job of easy pack up. You leave the jockey wheel in place and just remove the leg in 10secs .