Yep, the slants can be used to inoculate a starter, but you will have to step your starter up. That is, inoculate a 250 ml starter first using the slant,
then pour that into a 1000 ml starter before pitching. The slants are fine to be kept in your fridge for a few months before loosing viability.
Dave, I can pick you up on the way over if you would like.