My Nan's Vanilla Biscuits

This recipe is in ounces as well, its my Nan's and it just seems wrong to transpose it to grams...

The biscuits
6oz butter
6oz sugar
3 egg yolks
1/2 tsp vanilla
12 oz plain flour

- cream butter and sugar until pale
- beat in egg yolks until well incorporated
- add vanilla
- fold through flour
- turn onto a floured kitchen bench, roll out until about 1/2 cm thick (you can do them thinner if you like a crispier thinner biscuit)
- cut out into shapes, place on baking tray and bake for 10-15 minutes until lightly browned around the edges.
- Cool
- Ice with traditional lemon icing.

The Icing
I don't have measurements for this as I've been making it since I was about 8 and the quantities vary every single time:

A good amount of icing sugar (probably 2 cups)
A lump of butter (probably a big heaped teaspoon) - melted
Lemon juice
Boiling water

- mix the icing sugar, butter and a swig of the lemon juice - add more juice and/or water (taste as you go along and you'll know which one to add) to get a good spreading consistency.

Eat until you feel a bit sick from all the buttery, sugary, lemony goodness.