Pre-heat the oven to 220C/gas mark 7. Heat a good knob of butter in a frying pan and fry the shallots for a minute without colouring. Turn up the heat, season and fry the partridge livers and chicken or duck livers for a couple of minutes, stirring every so often until lightly coloured and pink, then stir in the sherry. Transfer to a chopping board and leave to cool a little, then coarsely chop and mix and transfer to a bowl; mix well.
Meanwhile, season the partridges and rub the breasts with butter and roast for 15 minutes, keeping them nice and pink. Then cut the puffball into 2cm-thick slices, halving them if necessary, depending on the size. Lightly oil a ribbed griddle or heavy frying pan, season the puffball and grill or pan fry for 2-3 minutes on each side.
Remove the breasts and legs from the partridge and cut the breasts into 3 or 4 slices. Mix the red wine vinegar and oil together, season and add the elderberries. Spread the liver mixture on the puffball and arrange the breast and leg on top. Scatter the leaves around and spoon around the dressing.