the nosewheel was special rubber that earthed any static buildup in the airframe
Interesting! Very correct use of the term "earthed" in this case. But it will help naught when refuelling from a bowser, or that bowser should be similarly equipped. And even then, the surface must be conductive - a dusty concrete apron on a dry summer day would still leave the danger in place. What matters is that the fuel tank, and/or the filler cap, are at the potential as the source of fuel, nozzle or jerrycan or whatever.
@john ball: thanks very much, it isn't always easy to tell of one's less bright moments. Switching to metal jerrycans and funnel is a very good idea; otoh I see little advantage to earthing to the hangar frame. Though of course it can never hurt - and after an experience like yours one would naturally be doubly careful.
@C1: I do not think a wooden airframe would build up a lot of static, there is always a little bit of conductivity unless the wood goes so dry that in-flight breakage becomes a far more serious issue. But large amounts of synthetic stuff like the modern covering tissues are worrying, and reinforced fibres (glass especially) even worse. Perhaps it is another reason to prefer carbon fibre, notwithstanding the cost?