I take it you didn;t shop in M & S nor debenhams, they both offer an exchange on unsuitable items within 28 days. But that is an extra service, not a right, though because they state it on their reciept and on pos in store they have to abide by the policy.
If you have accepted the credit note it may be too late to ask again, but maybe if you had returned yourself you would have used better shopping skills than your husband and been able to negotiate better, so on the plus side, you can blame him. : )