To me it looks like a tin can but as long as it does the job what does it matter what it looks like,
However I too agree I would double check the load as people even advertise 7.5 ton horseboxes claiming they can take 4 horses when legally they can't.
I owuld want ot know the age of the vehicle and its history, they give no information adn htis would put me off.
What work has it had done, what needs doing and what is likely to be needed done. If they say nothing need doing I would doubt them and walk away.
It looks old and the asking price draws me to thinking its old and being a horsebox I would be more cautious about damage, floor condition etc I mean its your horses safety at risk here.
I would also want to know why they are selling it adn watch their facial response to the question.
Dropping othe eyes, looking down or away, hesitating on the answer or even answering too quick is all signs of being mislead.
Guess I am just over cautious, but you can't be too careful or trusting these days.