> An option to override automatic (un)archival of passes is also desperately needed.

PREACH. If you buy an open return (any time within 30 days of outward), Avanti set the expiry on both wallet passes to be the outward day. Which means your "valid for 30 days" ticket disappears almost immediately. Absolute shambles.

Probably intentional. Train companies do loads of shenanigans with tickets and pricing