Finally talked to Autosparky who is local Bosch and ABS expert and did the following after being initially motivated by this thread. Linked a wire each into both wires of rear ABS circuit at the plug under the seat. Ran them to the red handlebar switch. Now have instant off with a dab of switch. Whenever the ignition is switched on the ABS automatically resets. No need for a rocker type switch which has to be manually switched which is needed if you loop just one side of the circuit to the bar switch.
Have to say I did querie the sparky about apparently introducing a short circuit by doing it this way but he just smiled and said No. Before doing the 990 I alterred my 650 Dakar and have been running it for a month. Works perfectly. No ill effects whatsoever plus the bonus of automatic reset every startup.