It seems we get nowhere near the selection the US gets in tires.

Avon tyres - unsure? (website sux)

BFGoodrich
Appears to have ProfilerG in 245/45R16 but I couldn't find the 205/55R16

Bridgestone
only have 225/50R16 (no 245/45R16 in any tyre)

Continental Sportcontact are avail in:
245/45ZR16 and 205/55ZR16 (Note these are N1 Porsche Spec tyres)

Dunlop SP9000E
only 245 tyres are all over 18 inches (no 16 inch avail).

Kumho
Ecsta 711 and Ecsta 712
245/45R16 and 205/55R16 (speed ratings vary between tyres)

Michelin
Pilot Sport 245/45ZR16 (website sux -search for Porsche 928 S4 GT 5.0 rear)

Pirelli
no matches found

Yokohama
No matches found

At this stage Kuhmo, Michelin and Continental seem the only choices for me.
Of these 3 - are there any stand outs?