Lube for ignition barrel

Hi folks,
Brief question if you would be so kind - what is most suitable lubricant for ignition barrel (Defender Td5)?

My one stuck in the "start" position, I didn't hear it coz of other noise, so it burnt out my starter motor & killed the battery. Spectacular breakdown in clouds of smoke on the A2! Not happy.

I asked the mechanic (himself a big Defender buff) whether I should give ignition barrel a dose of WD-40 and he said ignition barrels reeeaaaally don't like WD-40.
I thought WD-40 could fix everything - maybe even Brexit if you sprayed enough in the politicians' ears - but apparently not.
I've got some of that weird graphite powder lube stuff or else some silicone "dry lube" spray. Is either of those suitable? Or else I can just order whatever you recommend off t'internet.
Many thanks in advance.
Best wishes,
Wayne.

When the ignition barrel started seizing on my old disco, I was advised to use the graphite powder. It was some years ago now so I can’t remember where I got it or who made it.

Graphite’s the norm for key barrels and locks.

Nice one, thank you.
I've got some of that in the kitchen so will squeeze some of that in. Brilliant. Appreciate your help guys.
Best wishes
Wayne

Ahh the wonderful overflowing cupboard under the kitchen sink. I think Narnia's in there somewhere.