Nope, I didn't check policies other than disabling the Win7 firewall and confirming the validity of the share from another Win7 loaded PC, so it should have been 'legs akimbo' for RISCOS.
Suspicion exists that the router may not be entirely RISCOS compatible
Whenever IP is assigned by DHCP the connection does not last more than a few minutes and then RISCOS loses connectivity although the router continues to report it's attachment
. Assigning a static IP at both ends seems to solve much of that, although I had to reboot RISCOS in order to access the share that was working yesterday, so maybe it takes longer for the connection to go flaky with static IP? I'll dig out an older 100mb router and see if things improve, if not I'll try another pi with RISC OS to see if it's the hardware or not, at some nebulous point in the future.. but for the moment I am happy that I have repeatable access to shares. That will make life so much easier when it comes to reloading the system for when I FUBAR it, because I almost certainly will