For the pickled lemons, in a pan over a gentle heat mix 150ml/5fl oz water, the vinegar and sugar together.
When the sugar has dissolved, remove from the heat and set aside to cool.
Thinly slice the lemons, discarding the seeds, and place the lemons into the pickling liquid.
Place in the fridge for 48 hours before using.
To make the dressing, take the olive oil and 110ml/4fl oz of the pickled lemon juice, mix well and reserve.
For the mackerel place the sugar, salt, lemon and lime zest, coriander seeds and peppercorns in a bowl and mix well. Lay onto a tray and set to one side.
Gut and fillet the mackerel. Run the tip of a sharp filleting knife down either side of the pin bones and bloodline in the centre of each fillet and gently remove this area by pulling it away with a pair of fish tweezers. Spread the citrus cure on to a tray and place the fish fillets on it, flesh-side down.
Cover with cling film and refrigerate for two hours.
Rinse the fillets under cold running water to remove the cure then pat dry with kitchen paper.
Heat a griddle pan until very hot.
Lightly rub the mackerel skin with olive oil, place skin side down on to the griddle for two minutes, remove and continue to plate the dish.
For the garnish juice a third of the cucumber and reserve the juice.
Peel the remaining cucumber and then cut the 4 sides off the cucumber to leave you with a rectangle heart of the cucumber.
Cut the cucumber sides into 5mm/¼in pieces and set aside.
Heat a griddle pan until very hot.
Season the cucumber hearts and drizzle with olive oil, place on the griddle and cook for two minutes per side until lightly coloured and soft.
In a hot pan, pour a thin layer of olive oil and add the cut cucumber pieces. Leave to colour on one side, then gently turn to colour further.
Reduce the heat and add the shallots and garlic and cook for two minutes.
Deglaze the pan with the Chardonnay vinegar and reduce until almost all gone.
Add four tablespoons of the cucumber juice, broad beans, peas and herbs and heat gently to ensure the mixture remains moist. Season with salt and freshly ground black pepper.
To serve, pour the vegetables into the centre of a large plate, lay the grilled fillets of mackerel on top. Lay the pickled lemon slices over and around.
In a bowl dress the pea shoots with the lemon dressing and place onto the mackerel.
Sprinkle with a little more lemon dressing and a generous pinch of sea salt.
Sprinkle with broad bean flowers if you have had the satisfaction of growing your own broad beans.