'87 Coupe - electrical fault?

["Lorne Colmar" <lorne@lcolmar.freeserve.co.uk>]

Anyone had the misfortune to experience the following problem and/or
know what's causing it?

I've got a 1987 Coupe (European spec) with the 1781cc engine. A few
weeks ago, the car successfully passed the annual UK roadworthiness
test quite happily. Typically, a few days afterwards it started
playing up.

Problem: engine cuts out without warning, usually within a half mile
of starting.

Symptoms of problem: car starts first time and drives normally until
cut-out. The fuel gauge, temperature gauge, indicators etc don't work
at any point though, which leads me to suspect an electrical fault.

The fact that the car cuts out so soon after start also suggests
there's not a temperature problem. With the symptoms above, I suspect
some kind of electrical cut-out is kicking in but I'm at a loss as to
the whys and wherefores of this. Battery, alternator and earthing have
all been checked and are fine.

Any thoughts?

Pulling my hair out

Lorne