First make the batter. Mix the flour and the salt. Make a well in the centre and break in the eggs. Add a little of the milk. Gradually start whisking the flour into the eggs and milk, drawing it in to make a smooth batter, adding a little more milk as it thickens, until all incorporated. The batter should be pleasingly smooth and almost distressingly thin. Stir in the herbs.
Start the gravy before the toad in the hole, so that the onions have plenty of time to brown. Fry the onions in the butter over a medium heat until tender and well browned. Sprinkle over the flour and stir, then gradually stir in the stock and the cider. Season with Worcestershire sauce, soy sauce, salt and pepper. Leave to simmer, stirring occasionally, until the toad and his pals are ready. If the gravy gets too thick, stir in a little water.
Prick the sausages all over with a fork. In a roasting tin, add half the olive oil. Heat over a punchy, lively heat, then add the sausages and brown them quickly. Set aside. Now add the mushrooms and fry those until softened. Return the sausages to the tin together with the cherry tomatoes and remaining oil and heat through in the oven for 5 minutes. Stir the batter mixture once more and quickly pour into the tin. Whip it instantly back into the hot oven and leave to bake for 35-40 minutes until puffed and golden brown. Serve straight away, with onion gravy.