Hello all!

I drove to the gym tonight about a 3mile drive, did my gym session, came out, got in the van and no go!
All ignition lights are lit up but no glow plug illumination on the dash.
Immideately I thought its a sticky starter.
Engine still just warm so 3 of us tried pushing it to push start it and would it fuck go!
So phoned me good ol' dad for a tow start and as soon as he arrived I tried it one last time and glow plug light lit up and vrooom it dived into life! Mother fucker!
Drove home, got on drive, turned it off and it fired up again no probs.
Left it an hour or so and same prob again.
Sat there thinking of doing a Bazil Faulty on its ass and noticed even when the keys are out of the ignition, the air bag light, battery light and handbrake light are ever so slightly illuminated (could only see as it's dark out).
I have only owned the van about 6 weeks but since I got it the battery light has been permanently on but the battery shows 12.5 volts with engine not running and over 14 volts with the engine running so its defo charging.

Any info would be massively appriciated!!!!
Many thanks in advance, John.