I showed Hungarian grazing rye in my initial forest garden.
I experimented with clover, and the indigenous red did best.
Facelia too.
Perennial brocolli is a winner too.very sturdy, I grow in clumps of three. They grow to three feet tall and last 3 to four years harvesting late March to April.
I planted various willows and raised the pH with local limestone and fine grit.
This makes a home for worms, which would be introduced from a previously set up worm farm. It's easy to do this yourself.
Word of warning here - there are lots of flat worm on Skye, so try not to introduce plants and especially manure.