Welcome to GoY, Neil. As you will be well aware, your main issues on Shetland are wind and rain. So, trees and tall growing plants do not come into consideration :-(. You say that the garden is well drained so the shorter bulbs like crocus, shorter narcissus etc should do OK as should your idea of a wild flower meadow. At 40m the garden is rather long and I would have some concernes about the 6 inches of fresh topsoil being washed away down the lane before it gets consolidated. If the garden is on any sort of slope can you incorporate stone terracing to divide the garden into smaller plots, to reduce the risk of soil erosion?
In the crofting regions they will mow the meadows in summer for hay. This is after the spring flowers have flowered. If you do this the herbage will be easier to cut than in autumn and you can plant later flowering bulbs such as autumn flowering crocus.

hello Murray
i too live in an exposed area, on the west coast of wales. great advice from Bb...
as for the wind i have found that if u create shelter belts its amazing what u can grow. i use gorse, hawthorn, pampas grass, willow and magalanica fuchsia in my front line wind defence.... all grow well on my poor soil and give great protection to less wind hardy plants.

Thanks for the advice folks.
Its amazing that there is ways and means to get things to grow on the worst sites.
Will drop a few more questions as I try to make our site blend into the scenery
will some colour and shelter.
Neil