The potting shed
Peter, I'm not sure I am quite clear. Are you growing plants in the ground or in pots/raised beds? Many people (like me) make compost out of garden waste/kitchen, like you, but it is no good really as a potting compost. It's good for improving the matrix of the earth you plant into.
It's not a bad idea to plant directly into home made compost but it's unlikely the plants will thrive. From the many discussions on the forum, this seems to be the consensus. Homemade compost is good as a mulch and for opening up soil and making it better for water retention.
Does that help answer your question?
The plants are not in the compost/mulch alone. I thought it was clear by now that I have been mixing 'it' with the clay soil, in fact with the rotovator, to improve the soil.I believe there is some nutrition in the compost as it contains a high percentage of well rotted leaves.