This is now working, surviving reboots/power offs and I have put my previous attempts down to ‘operator error’.
I installed wireless-helper first and then SMB 3.6.25-1, set the mapped drive up via Explorer with reconnect at sign in ticked and connect using different credentials ticked (I used root and 0000 as I am more likely to remember it). When first asked for a username I just used root and did not need to enter a password. The drive then appeared in the left pane of Explorer as a mapped drive and appeared showing the disk usage in Network Locations within This PC/My Computer (wireless-helper on just its own did not resolve the issue).
My T2 was also infrequently appearing or not appearing in Network (lower left pane of Explorer) so I installed WSDD2 as well; however I did not need this to get the mapped drive working properly as wireless-helper/SMB 3.6.25-1 did the job without needing WSDD2. What I did find is if WSDD2 is installed with wireless-helper also installed but not SMB 3.6.25-1 also installed an error will show in Network (lower left pane of Explorer) saying incorrect program usage, if wireless-helper is uninstalled but SMB 3.6.25-1 and WSDD2 left on the error disappears but then you are back to the T2 infrequently appearing or not appearing.
All I need to do now is work out why Kodi on my Firestick keeps asking for a flipping password and won’t just accept root as the user with no password the same as the laptop will when accessing the T2 via Samba when I do not have it setup as a mapped drive. But that’s another day…………………………………............