I've seen a similar set-up on a VW trike being towed to the Shepton Mallet show, but can't remember what make it was. Is that towing lug a standard fitting on Boom trikes then? Presumably you have lugs on the towing frame to ratchet-strap the front wheel in place?
As for lugs on BOOM as standard, not a clue, vut they are easy enough to weld on.
There is NO need to ratchet the front wheel on, see it in action below. The frame acting as pivot point has the entire front end keeping wheel in place. To get front wheel out you would have to put towing vehicle into a negitive G dive.
Finished and painted, showing it in use.

Baddons Trike

Baddons Trike