Trim and finely chop the spring onions. Trim and slice the courgettes diagonally into slices around ½ cm thick.
Warm 1 tbsp olive oil in a deep frying pan. Add the spring onions. Season. Keep the heat low. Stir and fry for 4-5 mins till the spring onions are starting to soften.
Add the courgettes to the pan. Stir it all together. Add 100ml cold water and cover. Cook over a very low heat for 25 mins till the courgettes are tender when pressed with a fork. Stir every so often.
Remove the stringy bits of the beans by running a veg peeler down each side. Slice into bite-sized bits. When the courgettes have 5 mins of cooking left, stir in the beans. Cover. Cook for 5 mins or till the beans are just tender but still crisp.
Finely chop the mint leaves. Put to one side. Zest the lemon. Add to the courgettes and beans.
Warm 1 tbsp olive oil in a separate frying pan. Add the lemon sole fillets. Fry for 3-4 mins. Flip them over. Fry for another 3-4 mins till they’re golden and cooked through.
Stir half the chopped mint into the courgettes. Taste and adjust the seasoning. Serve the lemon sole with the courgettes and wedges of lemon for squeezing. Scatter over the rest of the mint leaves.