Woodland trust are giving away packs (sized on available land and location).
https://www.woodlandtrust.org.uk/plant-trees/
I know because I applied and have been successful. Mine arriving Feb/March next year. A simple enough 1 or 2 page online form.
I called our co-working office a 'community group', which seemed to be sufficient to qualify. We will be planting them in an area about the size of 3 tennis courts, which is alongside the old railway platform at Newhaven. Right before the bridge a few hundred meters up from Milk cafe, as NEPN passes under Craighall Rd.
Following the building of the new Sainsburys there is no longer any vehicle access possible to it other than along the NEPN, so it is effectively abandoned.
Anyone with space and permission* should apply and lets have a few more trees in Edinburgh.
*definition of permission i suspect could be flexible in this scenario as it is generally a good thing