I don't think it has been defeaning. Poll Cards are posted by the candidate either first class , second class or by DSA. That candidate pays for that delivery service and therefore Royal Mail are obliged under their licence to delivery it by that spec. The only difference between the normal first class , second class or DSA that you deliver every day is you also get a payment for delivering the Poll cards. Now if your an office that normally cuts off and they the poll cards will be over your model week than there should be sensible and pragmatic discussions.
With regards to all other election material addressed you have 3 days to deliver.