By that time, the Hospitallers were going through a re-branding exercise and had taken on Red with a White cross.
Of course, you are right

Thus proving I am a clown
I just had the St John Ambulance uniform and logo in my head. They are of course members of the Venerable Order of Saint John, so maybe black and white for the rank and file might still work. It certainly has that menacing ultra-religious look to it though.
Actually, red with white trim does sound quite appealing, but I'd have to do some sort of mock-up of each to see which looks best. A couple of boxes of Zouaves are definitely on my Christmas list.
Something else to ponder.....
I'll have two seperate units for the Knights of Malta. One will be a unit of 'knights' in steam augmented armour, along similar lines to this unreleased Foundry figure.
That's a great idea. It's got me thinking, maybe Ironclad's "Ironcladman" mini would be a fitting armoured knight.

I still haven't painted mine yet. Perhaps knights in red with white trim, others in black and white.