Where fresh peaches are to be used, prepare the curry sauce in advance, leaving the preparation of the peaches until nearer serving time.
Measure the oil into a saucepan, add the finely chopped onion and cook gently for a few minutes until the onion is soft but not brown. Stir in the curry powder and cook for a few moments then add the stock, tomato purée, lemon juice and chutney or jam. Bring up to the boil and simmer gently for 5 minutes to concentrate the flavour. Strain into a basin and leave until quite cold.
Lightly whip the cream and whisk in the curry sauce. Scald the fresh peaches in boiling water for 30 seconds and then peel away the skins. Halve and remove the stones. Arrange the peach halves in pairs on crisp lettuce. Spoon over the curry sauce and serve.