OK, further looking into my Haynes Transporter manual showed that
the "approximate" diagrams weren't too bad at all, surely more accurate
than Bentley which describes only US models.

What was confusing me the most was that the 1986-1991 European models are
some kind of hybrid of the 1993.5-1985 and 1986-1991 US models, i.e. they
have Digijet and no catalytic converter but do have the Idle Control Valve
(and associated control unit) like the US 1986-on models (but not
Digifant).

The Pre-1986 European models were probably quite similar to the US models
(Digijet + no catalytic converter).

CTM