The Hexham Abbey website has a page showing the burials in the Northern Graveyard: https://www.hexhamabbey.org.uk/heritage/Ledger/NorGra.html and if you click on the circled number ‘15’ you should see catalogue record for the gravestone you mentioned: https://www.hexhamabbey.org.uk/heritage/Calm/HEXAB1267.html; it is still there but neither the Abbey nor the local council has the resources to keep these gravestones free from encroaching turf and grass clippings. (Any volunteer gardeners?)
There are other Carr gravestones at the Abbey, including https://www.hexhamabbey.org.uk/heritage/Calm/HEXAB1056.html (1715–1750) in the north chancel aisle.
