Come on Trampboy sort it out!
Start with the simple stuff:
Take a plug or two off and have a look. What condition are they in?
Do a quick paper clip trick on the ALDL for any clues.
Like avengador1 mentioned, attach a (temporary) ground (wouldn't bother removing the old one to start with), can get a new cable from Halfords (when you go in to get those exhaust clamps!!! ). Paul T made a post about an easy ground cable position not long ago with a piccy...might be worth giving him a shout. Take the car for a spin and see if things are improved.
After this I'd go for leads and things, although I don't think this would explain your non-starting episode.
Are you visiting at the weekend? Hopefully the Landy will be done(ish) and RUNNING by Saturday , so should have time to fix yer Rodney D tips.
As for O.C.W (who sell AC Delco parts here in the UK), well perhaps it is linked to their appauling lack of respect for their customers, inconsistency, rudeness and general incompetence (thats been my experience anyway). I hope that someone competent takes their place and continues to sell AC Delco parts without the O.C.W. attitude. If you need parts let me know as I'm gonna place a US order soon.