Why do that type of paint job just to sell. They have restricted who will want to buy it . I should think most buyers will be put off by the paint job.
The ad states that it has a 50mm hitch It does not, it has the original Bonair USA style hitch which is 2" , which will be dangerous to use on a 50mm ball.
Even if a 2" towball could be found somewhere, it has no handbrake, which makes it illegal for European use.
What's more, the braking system is hydraulic, and both the Bonair hydraulic system and the Bendix system (used on other early USA campers like Jayco & Starcraft) barely functioned even when brand new - which is why USA manufacturers now all an electric system for their braked trailers (and have done so for nearly 30 years.
Anyone towing that trailer on a UK public highway is asking for a fine and licence points if VOSA take an interest.
I was incorrect about the handbrake - it does appear to have one (of sorts)
The overrun system is still hydraulic though, The Bendix hydraulic hitches were a bit weird - and the Bonair system was even more odd. If I remember correctly, the horizontal overrun movement was somehow translated into a vertical movement at the hitch master cylinder all very peculiar.
Then, of course, comes the problem of finding master cylinder and wheel cylinder seal kits.. Years ago you could buy Bendix seals from Conway - they stocked them for the early Jayco models they imported, but they didn't like selling them to Starcraft owners (Starcraft had the same hitch) so you had to tell them that you wanted the seals for a Jayco model like the Jayfinch or Jaythrush.
As for Bonair! - I don't know who imported them, but there is more chance of being carried shoulder high to Italy and being proclaimed Pope than of finding a set of seals for them!
The 2" hitch could be a seriously real problem - even when brand new they were 'rattle loose' when used on a 50mm ball. After 34 years of wear and tear the hitch will remain in place on the ball only by a combination of high nose-weight and fervent prayer...