Place the biscuits in a plastic bag, laying them out flat then, using a rolling pin, crush them to fine crumbs. Mix them with the butter next and press them all over the base of the cake tin. Now put the rhubarb, ginger and sugar in a pan, then cover and cook very gently until soft but not too mushy. In a bowl, beat the eggs, then gradually beat in the cooked rhubarb and juices. Return the mixture to the pan and stir over a low heat until it thickens, but don't allow it to boil or it will curdle.
Then remove the pan from the heat, beat in the curd cheese and leave to cool. Now, in a small bowl, or old cup, mix the gelatine with 2 tablespoons water. Leave to soften for a few minutes; then stand the bowl in a pan of hot simmering water and stir until the gelatine liquid is clear; then strain in the rhubarb mixture. Next, beat the cream to a soft, floppy consistency, then fold it into the rhubarb mixture and pour it into the prepared tin. Cover with foil and chill for several hours before serving.