Heat oven to 200C/fan 220C/gas 7.
Oil and season the potatoes, then bake for
1 hr until a knife slides in easily and the skins
are crispy. Cool for 10 mins.
Halve the potatoes lengthways and scoop
out the cooked potato into a bowl, leaving a
thin layer behind so that the skins still hold
their shape. Mash the potato with the butter,
mustard and seasoning, then stir in the
spring onions, 175g cheese and kidney
beans. Pile the mixture into the potato skins
and scatter with the remaining cheese. Can
be made to this stage a day ahead and
chilled. Bake for 30-40 mins until golden.
Serve with the sausages and salad (see 'Goes well with').