Thought I was the only soul on the internet who'd encountered that problem. Figures if anyone else would have bumped up against it, it would be you guys 🙂
for future reference, this was an unexpected self made problem, I selected the dev channel as was tempted to try the latest pfplus 22.05 beta but never upgraded, this however I found sets packages to the same channel so 0.1.6_2 isn't compatible with 22.01
On the Windows box with the share, goto firewall. Inbound connections.
Find File and print share, SMB. Hit scope tab and allow all. Was set to Local IP only.
She logs in and is asking for credentials. Perfect, exactly the direction I was looking for. I normally only log into linux box's via VPN. So I forgot all about that.
Solved by watching a video from Christian McDonald. The change was to the settings in the peer (client) app. I set the DNS address to the tunnel address (192.168.85.1) rather than my pfSense address.