Hello, I'm living on the isle of lewis (in the hebrides). It's probably not quite as extreme as the shetlands, but probably similar problems. I managed to grow kale, brussel sprouts, potatoes, carrots, and beetroot. The kale was the easiest - I just stuck it in the ground and it looked after itself. Anything more tender than these just seem to shrivel and die in the wind. Oh broad beans seemed completely unbothered by the wind as well - and jerusalem artichokes.
Also digging drainage will help. And I've started putting in hedging for shelter.