Jim,
Nowhere does he say he has never seen one - you made that up

It is ludicrous to suggest he had seen other examples and not mentioned it in that article.

If they really were "common throughout Britain" we who live here would have seen one.
We still haven't.

Rag, I doubt that travellers haul their caravans behind them to the pub.
"Hobby" is just a large German manufacturer of large caravans. Your signs refer to sites. Recreational sites are not all suitable as stopping places for travellers who will often want to run their businesses from the site.