The message
from "Rupert \(W.Yorkshire\)" contains these words:

snip

The website at Rowlan explains the different type of topsoils.
http://www.rolawndirect.co.uk/page.p...category&cid=8
(about £500) for your requirements.
I have never used their topsoil but can vouch for the turf quality.

There was a company, IIIRC, on Mendip called Green Ore - not too
far from Wells. I googled for them and came up with the website Rupert
mentions.

In the past I have used their potting composts and they were good. No
idea about topsoil though and not sure if they are still there.

Have you tried asking at local nurseries/garden centres?

Riverside in Bristol - Brackenwood Garden Centre, Abbots Leigh
- Cleeve Nursery and Garden Centre, Cleeve - Burrington Coombe,
which is now White something, are ones that come to mind as being
practical and helpful.

Jennifer - in Bristol