Wood planks/decking/pallet collars/scaffold fo my allotment (St Nicholas SG1)

Hi all
I am looking for some long planks of wood or old decking boards that are 4in wide or more that I can use to build a nice neat edge around my new allotment. Also scaffold boards or pallet collars (those hinged things) to make raised beds.
Can collect pretty much any time.
Many thanks for reading