Paul, I think Saab still does the electrical schematics for the '96-'98 (here in the 'States, it covers all the OBDII models).
Rumor has it that the older version Trionic ('93 1/2- '95) is no longer available. I have a few copies of the Trionic, AC, EDU, 2 speed fan, etc. schematics, but not the complete Electrical System service manual. If you only need the Trionic schematics, they're available in the 2:7 Engine management system manual. Anyway, a Saab dealer, over there, should be able to help you. I'd offer to email a copy, but my digital cameral is down, and I don't have a scanner
Also, AllData seems to cover electrical data that for UK models. At least, I haven't yet found a discrepancy between their schematics and my '96 Aero. It covers both OBDII and non-OBDII for that year. Don't know whether that goes for later years (OBDII was introduced on the '96 US models, I believe).
The AllData information appears to be based on (and largely scanned from) the factory manuals. I've found it quite useful.
Mark is correct. As far as I know, no UK-spec. 9000s have it. It became a requirement for US-spec. cars in '96, and is intended to allow for interrogation of the system during vehicle inspection (which is why it was standardised). The reason I mention it is that the wiring is slightly different to accommodate things like a second lambda probe after the cat, etc.
I don't have a factory manual. I'm told that of all the Saab manuals, the appropriate electrical manual is by far the most useful.