I just subscribed to the yahoo groups several minutes ago.
I'm using a program called PG Offline to backup all the messages of the list. I think will take an hour so I hope I will download all messages.
I will provide a SQLite database when it's finished.
I also downloaded all group files, photos and links with the same program.
I recommend to save the member list from yahoogroups. Just in case.
https://es.groups.yahoo.com/neo/groups/Traveller_TNE/members/all
Actions --> Export --> CSV
And now, I'm going to sleep. In Spain it's 2:22 AM and I have to work tomorrow.