Heathrow outage

Due to fly soon to LA with booking using Select Vouchers. Hopefully the outage will be resolved but has got me wondering.
If our flights are rescheduled a few days later, we can no longer go due to work and miss our arrangements we had planned for LA by arriving late. Normally can claim a refund, so would they refund the select vouchers but with new expiry dates? these were due to expire in June this year?
Would we still be entitled to compensation under delayed/cancelled flights even though this is a reward flight booking.
Thanks
If our flights are rescheduled a few days later, we can no longer go due to work and miss our arrangements we had planned for LA by arriving late. Normally can claim a refund, so would they refund the select vouchers but with new expiry dates? these were due to expire in June this year?
Would we still be entitled to compensation under delayed/cancelled flights even though this is a reward flight booking.
Thanks