Preheat the oven to 230°C/450°F/gas 8. Half-fill a large saucepan with cold water and add a tiny pinch of sea salt. Place on a high heat and bring to the boil. Meanwhile, give the new potatoes a good scrub with a scrubber, then on a chopping board cut any bigger ones in half, leaving the smaller ones whole. Cut the tips from the runner beans until you cut into the stringy piece that runs the length of the bean. Pull the stringy bit and peel it down the length of the beans on both sides of each one, then slice at an angle into 5cm pieces. Trim the stalk-ends from the green and French beans, if using, but leave the wispy tips on, then slice the beans at an angle into 3cm pieces. Once boiling, carefully lower the potatoes into the water with a slotted spoon, bring back to the boil, then cook for around 10 to 12 minutes (depending on the size of your potatoes), or until they’re nearly done. Meanwhile, if your peas are still in their pods, pod them now. When the time’s up on the potatoes, carefully add all the beans to the pan and cook for a further 4 minutes. Drain the potatoes and beans over the sink into a colander and steam dry for a couple of minutes, then tip into a 25cm x 35cm roasting tray. Scatter over the peas, dot over the butter and drizzle with 1 tablespoon of olive oil. Use a microplane to finely grate the zest of both lemons onto a chopping board, then scatter into the tray. Cut the lemons in half. Squeeze the juice over the salmon and vegetables, using your fingers to catch any pips. Season lightly with salt and black pepper, then toss together while still warm so that the flavours are absorbed. Pick the basil leaves, discarding the stalks, then roughly chop them with the fennel tops or dill. Scatter half the herbs into the tray. Carefully score the salmon fillets lightly on the skin side. Rub each fillet with a little salt, pepper and olive oil, stuff the scores with the remaining herbs and place on top of the potatoes and beans, then wash your hands. Bake in the hot oven for 10 to 15 minutes, depending on the exact size and thickness of your fillets, or until the salmon is cooked through and the vegetables are soft. Divide between your plates using a fish slice, then drizzle with the cooking juices from the bottom of the tray and serve.