The message .com
from "deano" contains these words:

Anyhow, the owner would now like the barrier re-instated using metal
(motorway style) rails, or something along those lines. Each bay is
just over 8' wide and needs to share fixings on each post with the
following bay, i.e. there are 2 holes per post, one above the other.

Why not just use a bit of box section steel?

--
Skipweasel
Pay no attention to that man behind the curtain.