Well I've had a good old look into the starting shenannigans on the '79 diesel 88.

issues -
earth cables - not enough of them and new main earth isn't sufficient
battery - too lightweight
fan belt - too old
starter motor - not in good shape
alternator - bearings on the way out
fuel filter - full of snotty bacteria

all of which is conspiring to make starting an act of faith rather than certainty.

This S3 is actually a work vehicle, therefore, quite unlike me, I went shopping at Mssrs Paddock and Paddock and have a new starter motor, alternator, fuel filters and fan belt on the way. I usually rebuild alternators and starter motors but these landy parts are a lot cheaper than other cars i have owned so I'll recondition them.

A nice shiney new 110amp Lucas battery has arrived as well jag V12/Iveco van spec so should have the colhones to deliver!

Also - ordered 2 adjustable tow hitches and a NATO hook, long story but we have a variety of trailers here and need to be able to swap tow hook types from ball to jaw to NATO at short notice.

All will be fitted tomorrow and the S3 will be pressed into service

What are the glow plugs like? I know mine used to be tricky to start without using glow plugs!

Also check that the lead going to the starter from the battery is good, on mine it had been chafing and had rubbed through the insulation which meant bare wires which had started corroding (means not as much current gets through as it should)