Montagu arms

Detail on the main West Doors of Bath Abbey.

Note the 'ES' on the right is part of the word 'EST' which may be an engraving error introduced during one of the restorations of the Abbey by the Victorians. It should be 'ETC', as in:

ecce quam bonum et quam jucundum etc

See The Montagus and the great West Doors of Bath Abbey by Tony Pratt [PDF].