Marketing or leafleting campaigns whether they are conducted on a street, road, or other area open to the public, or by direct delivery to residential or business addresses do not require any form of licensing permission.
However, in the case of direct face-to-face leafleting from a public place, permission should be sought from the landowner due to the increased risk of littering linked to this activity. A fee may be payable.
The following links may be of assistance to you:
City and Parish Council contact points:
Information about Parish Councils