thanks all.

When I looked last last night, the clock was still showing the correct time, and the red light of the immobiliser was still flashing as brightly as it usually is. Perhaps it will start on Saturday.

Main reason for asking is that it's apparently quite common for Morgan's to have a flat battery after more than 1 or 2 weeks of non use -- at least that is what I have read on here recently. This is surprising to me.

Jump start pack is a good idea though. Is there an easily accessible attachment point (as battery is 'hidden' in front of the rear axle)?