 Walter attended Parliament on 29 April 1463 where he was rewarded with an exemption from the crown's Act of Resumption revoking various gifts and grants.On 18 June 1463 Devereux was appointed as Constable of Aberystwyth Castle for life, and 10 August 1464 joint keeper of the Haywood in Herefordshire.In late 1467 he was granted Oyer and terminer in Wales with power to pardon or arrest, and specifically tasked with investigating counterfeiting, clipping, sweating and other falsifications of money.