Vauxhall Combo wont illuminate glow plugs to start,after using a faulty electric tyre inflator!my bad

I used an old, un-tested electric tyre inflator in the cigarette lighter of the van.Working ONLY briefly ,it was deemed the inflator faulty. The previously perfectly working van ,then each turn of the engine became harder to get started,with once running the battery light would come on for varied time scales,especially turning right and the reversing light stopped working.we charged the battery by elimination,checked terminals,earth strap,wiring for possible breaks or shorts,bulbs and fuses,The van got worse and glow plugs would only illuminate if in reverse or lighter pushed in until glow plug light gave up and apart from brief flicker wont illuminate to start engine and requiring knowledge greater than mine i cannot get to self-employed work to earn and pay the call out fee + repairs of auto-electrician.Any suggestions of what can be done or looked at id be really greatful for clues to my problem