The delay was caused by a non-EU carrier on a flight not to the EU - no compensation is payable. You'll be able to get a refund of the fare difference (which likely isn't much on the return leg)

You may have some coverage from your travel insurance so that is worth checking

VS is showing 3 x PE seats available so it's worth keeping an eye on things in case it opens up further, though you'd need Comair or BA to reissue you back into PE which may not be so easy at the last minute!