Duncan,
Just buy a Lee mould in your calibre. There is an instruction sheet with each mould that tells you in a general way how to cast. Tells you to clean the mould, tells you to smoke the mould with a smoky match or whatever, tells you how to heat the mould, dip the corner into the melted lead till it hots up.
It IS a rather simple thing to do. People have been doing it for hundreds of years. A lot of them a little dumber than us.
I specifically mention the Lee brand, if you can get it, because the moulds are aliminum blocks, heat quickly, cool quickly, so the balls are ready to drop quicker, and they come WITH handles, and they are cheaper for the WHOLE thing than most other brands blocks alone, indeed, cheaper, I think, than the handles alone for Lyman and the like.
A double cavity is less than 20 USD, and a bottom pour melting pot, 10 pound capacity, is less than 40 USD.
Should you decide to get these, would you please let us know what they cost in either the UK or France?
Cheers,
George