[Cave-survey-archive] Adding members

Dave Irwin who chaired the sesssion is worth including. He told me that
he retained a lot of old Mendip survey data which could form the basis of a
pilot scheme.

I think if we trail the draft cave-specific fonts around other ongoing
discussion groups we might turn up constructive and supportive individuals
who could make a permanent contribution.

It would be nice to get the S.Wales cave surveyors on board but IPR is
still a very sensitive topic there.

Harry