Here’s the recipe again - save you searching.
Base:
4 oz margarine,
2 oz caster sugar ,
5 oz SR flour.
Cream marg. and sugar and mix in the flour - don't work it too much, it shouldn't be greasy.
Spread into an 11in x 7in baking tray, pressing into edges and corners but keep as level as possible as it will rise there anyway. Flour your hands or whatever you use to spread it.
No need to grease the tray due to relatively high fat content.
Bake 350 F/gas 4 (no idea of deg. C, possibly 160 is what I'd try in my fan oven which complicates any guesswork), about 10 minutes till light golden. Can easily burn so watch it.
Leave to cool in tray.
Fudge icing:
4 oz butter,
3 oz demerara sugar,
4 tbsp. milk,
8 oz icing sugar.
Dissolve sugar in butter over a low heat, bring to boil, add milk and boil till frothy, take off heat and gradually beat in icing sugar till it looks fudgy and starts to coat back of spoon, i.e. is ready to set.
Pour into tray quickly to get an even surface. Don't cut till completely cool and set. It will probably be fairly soft, especially the lemon flavour.
Lemon: use 4 tbsp. lemon juice istead of milk, and caster sugar, not dem.
Coffee: Strong black coffee instead of milk, and white sugar or light brown if you want something a bit less fierce.
Mum will be so pleased you like it, @TimeIHadANameChange.