Wash and scale herrings.
Roll up, skin side outside, from head end to tail.
Arrange side by side in 1-1/2 pint heatproof dish.
Slice onion thinly and put into dish between herrings.
Sprinkle with spice then add bay leaf.
Dissolve Marmite in hot water and stir in vinegar, lemon juice and sugar. Pour over herrings.
Stand strip of lemon peel on top.
Sprinkle lightly with salt.
Cover and cook in centre of cool oven (300 F or Gas No. 2) for 1-1/2 hours.
Remove from oven and leave until completely cold before serving.