Cook the potatoes for 15 minutes with a lid on until just cooked. Drain and once cool enough to handle, slice the potatoes into 1cm thick pieces. Keep the water and cook the green beans for 5 minutes and drain.
Place a griddle or frying pan over a medium heat. Toast the pine nuts in the pan for approximately 2-3 minutes - pine nuts tend to burn quickly so keep an eye on them. While the pine nuts are toasting, slice the courgette into ½ cm pieces and pop into a big bowl.
Add the sliced potatoes in the bowl with the courgettes. Add 1tbsp of the olive oil and toss everything together with a little salt and milled pepper. Place the potatoes and courgettes onto the griddle pan and cook together until nicely charred and keep warm. This may be in 3 batches depending on the size of your pan.
In a large serving bowl add the rocket, baby gem, green beans, mint and pine nuts.
Mix the lemon zest, juice and olive oil in a small bowl. Pour the dressing over the potatoes and courgettes and mix well. Then toss the potatoes with the salad and serve with the feta cheese crumbled over.