Yes, as Mark says, I was thinking of more 'formal' organisations, along the lines of the Boer War Vets Assoc.
BTW, slightly off my own topic here...is your Boer War badge the one with the covered wagon Mark? That's the one I have.
With regards to the idea that 'citizen soldiers' are keener than professionals to form associations; my two pennies worth is that it allows them to remind themselves, when they return to their offices, factories and shops, of what feats they are capable of. Maybe, as you say, the mess fulfilled that function for regulars, and anyway, they didn't return to mundane day jobs.
Thanks to you all for your replies...lets hope even more comes up!
p.s. I have opened a topic on the Boer War Veterans Association on the Boer War thread...please take a look