Put the caster sugar and rose water in a pan with 1 litre/1¾ pints of water and bring to the boil. Cut a small cross in the top of each peach, then add to the pan and simmer for 5 minutes. Take the peaches out of the syrup and slip off the skins, then return to the syrup and cook for 10 minutes until the syrup has reduced by half. Strain and cool.
Make the honeyed yoghurt by mixing together the yoghurt and honey, then serve with the rose-scented peaches and drizzle over some of the remaining syrup.