Broadback wrote:
Having a lot of well rotted compost and leaf mould I wondered what the
mixing proportions are for potting compost, also do I need to add any
fertilisers?

Hi,

Often leafmould and compost can be a little acidic, so adding some ground
limestome can be usefull. For general potting compost I mix 4 parts
leafmould, to 2 parts loam (riddled soil/turves), to 2 parts compost, to 1
part sharp horticultural sand with a bit of ground limestone thrown in.

I use this for growing on between seedling and planting out.
For seed I omit the compost and add more sand.
If I'm potting up something that maybe in the pot for a longish time, I
add organic chicken-sh.. pellets.