For the trout, place the wood chippings on the bottom of a metal old tray fitted with a grill rack. Lightly oil the rack and place it on top of the tray, so that (it is should be 4-5cm/1½-2in from the bottom of the tray).
Rub the trout fillets with oil and lightly season with salt and freshly ground black pepper. Place them on the rack skin-side down.
Cover the entire tray with a double layer of heavy-duty aluminium foil and seal very tightly around the edges, making sure that the foil is not touching the trout.
To cook, first ensure that you're working in a well-ventilated area. Place the tray on a very high gas flame to cook for two minutes; then carefully cut a little hole in the top of the foil with a pair of kitchen scissors (for the smoke to escape). Remove the tray from the heat and leave to rest (ideally outside) while you prepare the salad and pea purée.
For the salad, combine the oil, vinegar, shallot and a pinch of salt and freshly ground black pepper in a small saucepan. Cook gently on the stove for a few minutes so that all the vinegar is absorbed by the shallots.
Bring a pan of salted water to the boil, add the garden peas and cook until tender. Drain the peas and add to the shallots. Mix to combine; then add the chopped mint.
For the pea purée, cook the frozen peas in large pan of boiling water until tender. While the peas are cooking, pour the cream into a pan large enough to accommodate the peas as well.
Bring the cream to the boil, then reduce the heat and keep it warm.
When the peas are cooked, drain them and add to the cream. Cook for a couple more minutes.
Place the peas and cream in a blender or food processor and blend to a smooth purée. Pass the mixture through a fine sieve and season with salt and black pepper, to taste.
To serve, place a spoonful of pea purée onto the centre of each serving plate. Place a fillet of smoked trout on top and spoon the salad around. Garnish with pea shoots.