"TheScullster" gurgled happily, sounding much like
they were saying:

Anyway I digress - the point is, even if this guy knew chapter and verse
and came with excellent references (which he wouldn't actually supply),
I would have been reluctant to deal with him. His van, whilst having a
fancy logo job on the side, did not display a land line phone number or,
more importantly, a business address.
The lack of a displayed address makes me very wary - does anyone else
feel the same?

On a van? No, not really. TBH, these days, I wouldn't expect more than a
URL - maybe a phone number. A mobile rather than a landline says "very
small company", but is that necessarily a bad thing?

looks out office window
UKMail van, CityLink van.
Both have URLs and phone numbers, neither has an address.

This raises another question, aren't businesses supposed to display a
trading address on web sites by law, or is it just a vague "contact
details requirement"?

Yes, limited companies are required to display the registered address on
all communicatons.