This has just been flagged up on the Kickstarter page (these terms were in place when this project was started). I didn't realise that there was actually a breach here (assuming that we never get the rewards or the refunds).
'A Project Creator is not required to grant a Backer’s request for a refund unless the Project Creator is unable or unwilling to fulfill the reward.
Project Creators are required to fulfill all rewards of their successful fundraising campaigns or refund any Backer whose reward they do not or cannot fulfill.'