Rich there is no spare, just runflats. I once drove on 0 psi on the fronts, couldn't see any difference but steering was a bit peculiar.
Never seen a clear lens, always red I thought. This is a Switchboard No.1 Mk 6, yours should be a Mk 1. Early versions of that had smooth domed coloured lenses.
I have never seen Mks 2-5 apparently they are entirely different unit altogether, which seems highly illogical.
Servicing is something that can slip or be inappropriate here are a couple of examples. I'm not saying when, where or to what Humber they relate.
Here the torsion bar tension is incorrectly adjusted as a result the nut protector tube is not done up as it hits the anchorage lever.
Here the classic mistake of assuming all lubrication points must be greasing points. The correct instructions are clearly given in the User Handbook its even there in my 1953 provisional edition.
