Hi Simon,
I'm sorry i don't have an answer for you query, however i reckon you may be able to answer mine...
i hope i'm not breaking any forum rules, however my post is at
https://forums.openvpn.net/viewtopic.php?f=6&t=7069&sid=db8375053de32f9a84dc6a0061fdcdac
would you mind having a gander and letting me know if what i'm trying to accomplish is what's in your setup?
cheers