@Owen Jenkins - If your Miro account profile (by email) is a member of both teams, you should be able to use the Move to account open from your Miro dashboard and select the team/account/space (Miro has too many names for this):

You could also use the board export feature if need be.

If none of methods work, you could also have a read of @Kiron Bondale’s awesome writeup on sharing/moving boards → 6 ways to provide someone with a copy of a board you own