I do think it's sad that someone at the rally yesterday said she was nearing retirement and earning 9K a year less in higher education than she would have done if she'd stayed in teaching.

It's certainly sad that people are leaving teaching to go to lower-paid jobs. :-/ But I suspect that's not what you meant.

maybe that means I don't know enough to be justified in taking part in this action?

I don't think there's an entrance exam. :-) You clearly know enough to feel incensed by what's happening; what is the strike supposed to show, if not that people are angry about the situation?

I note *I* don't feel underpaid

I don't feel underpaid either, at just over 20K -- it would be nice to have more money, sure, but I could easily have got a higher-paid job if I'd wanted to, and instead I chose to do jobs I enjoyed more (and believed to be slightly more 'worthwhile' in some kind of vague woolly way).

I can't imagine earning as much as 35K a year -- I'm unlikely to ever earn that much, even allowing for inflation! -- but it doesn't really bother me. Maybe it should? I don't see that getting bothered by it would do much other than make me unhappier, though.