Sorry to be so late on this one - I've not had time to look on this bit of the board recently!
My handle stems fro aquiz team of which I was a member, back in the good old days at Ruskin College, Oxford. The leader of the team was a dogmatic socialist who had received the scathing comment from a worsted adversary (he had used some wooly arguments!) "You're just a Rhubarb Commando!" He named his team in honour of this soubriquet.
When I moved to Lancaster University, I bought a house in a village which is known locally as "Rhubarb City," so it seemed appropriate to apropriate the team's name.

As to age - it would seem I am a mere youngster at 61 (late November - Saggitarian con-man!)