Thomas wrote:

The cable that I bought has inners coloured brown, blue, black and
green/yellow. I wired the blue to the neutral and the brown to the permanent
live - leaving the black and green/yellow for the two switched lives. I have
a 3 pole isolator on all of the live cables, but even so, I'm not
comfortable with having a green/yellow for a potentially live cable and I'd
like to find a solution to this asap.

You're right to be uncomfortable, you're NOT allowed to use green/yellow
as a live, even if you sleeve it in brown. It can only be used as "earth".

What is the normal convention in these situations - is there a 4 core cable
with different colours made specifically for this type of installation?

You can get a 5 core flex suitable for your purpose

http://www.tlc-direct.co.uk/Main_Ind...e_3/index.html

Higher number of cores may be numbered instead of coloured.