ROYAL MAIL blocking disabled parking bays

Today Again a struggle to park in a disabled bay in Sainsbury's Cheltenham because a ROYAL MAIL van was parked in one of the bays, when confronted we had a mouthful of abuse and said that He had Sainsbury's permission to park there, but we spoke to the operations manager at Sainsbury's and this is not the case(which we thought anyway) because it would break there parking rules. There is 50 odd spaces where he could have him to parked. This gentleman is representing ROYAL MAIL.