Pulling hair out now...
Took the bike to the main dealer, who checked everything (and sold me a new chain!!) and reset the error code. Great, I thought. 12 miles from the dealer, the error code was back on!!!
Tried everything on return home but to no avail.
Took bike in for its 1st MOT, and bloke told me that if it was a car/van etc., it would fail on the EML being on! Also found inner brake pad had 'moved' slightly and was sitting at an angle so only the top 25% of the pad was touching the top of the disc. No fail, as the brakes tested fine.
Jumped on the bike to go home and order yet more parts, and the error code had disappeared!!!
Replaced brake pads and spring clip etc., took bike out for a test ride and still no error code. Enjoyed the next week or so with a clear dash display, until.. yup, error code back on.
Although the bike runs fine in this mode (no ABS light on, and no strange engine running), it obviously masks any other potential issue.
Annoyingly, Suzuki do not seem to have a technical centre - they just refer you to a dealer.
I'm off to Spain and France in September, and I am now seriously considering getting rid of this bike... Shame.