Spy,
"Also the A321 flies down the approach very close to VLS so not a lot of room for error"
VLS is computed by a different computer to the IAS and Airbus have now confirmed that the small amount of space between the two is not a problem!?
Haven't scraped the tail of an A321 yet but never say never. My advise (for what it's worth) is leave the power on for a little longer after the 'retard' and accept a hard landing if it's all falling apart.
Good luck to the Monarch crew.