I just use a basic sponge mix -
175g (6oz) Butter, Caster sugar & Self raising flour
3 Eggs
100g (4oz) Glace Cherries
2 Dessert Spoons Boiling Water
Cream the butter & sugar well (5 mins mix with an electric whisk) until it is almost white. Whisk the eggs together in a jug and add 1/3 to the mixture and mix well. Keep adding the egg little by little. If looks like it is starting to separate then add a spoon of the flour to bring it back together and continue with the egg.
When all the egg is added, sieve the flour and stir in with a metal spoon. Cut the cherries in half and add them at the end.
Just before you put it into a loaf tin, add 2 dessert spoons of boiling water and mix it in. Bake 180 for fan assisted or 200 electric, gas mark 5
The cherries normally sink if the mixture is too wet, this recipe always worked for me, and I have been using it for over 20 years.