Could it be contaminated or just difficult to strike? Both ends are glowing whitish so should both have emitter on their cathodes?

That's what it could be, difficult to strike, I'll need to try a starter that takes up to 125W tubes so that the 'overstrike' will hopefully jumpstart this tube back to life - I'll post an update if I get anywhere

Update: Tried everything from a plasma ball to a bigger wattage starter - no good

Is there any end blackening?

Looks like the tubes lost vacuum.

Have you tried it on HF? Sometimes an electronic starter or a manual start with a stuck starter can work, but it does sound like it is contaminated sadly

I haven't tried that one yet - the electronic HF ballast, need to wire up the Fitzy fitting that has that b.a.g branded ballast and to see if that works. I've tried the Philips S10-E electronic starter and the EOL protection cutoff kicks in