I have not looked at this copy. Nicholas Vincent believes it was made from the engrossment of the 1217 Charter at Gloucester.1
The Letters and Charters of Cardinal Guala Bicchieri, ed. N. Vincent (Canterbury and York Society, lxxxiii, 1996), p.30. Since 1996 Register A has been divided into two volumes. It would seem that the copy is in what is now C. Breay, J. Harrison and D. M. Smith, Medieval cartularies of Great Britain and Ireland (London, 2010), no.455B.