John Felstead

Problem solved. Rather than using an electrical connection I overcame the issue mechanically. When the board was mounted in the box I drilled a hole directly opposite the switch and inserted an old self propelling biro which I cut down to the right length. I left the spting in place but removed the latching mechanism in the lid. Pressing the top of the biro activated the switch🤪

Thanks @bedna  Ive now got it working with read write execute on the share via Windows. I searched the Ubuntu forums and foud a couple of posts relating to the issue I was hving with an exfat formatted hard drive. For anyone else searching this forum the answer was to edit the fstab file as follows:
 
To enable read-write access for an exFAT drive in /etc/fstab, add rw,uid=1000,gid=1000,umask=000 to the options field. Using umask=000 ensures all users have read/write access, while setting the uid and gid to your user ID (typically 1000) assigns ownership to your account.  Also from Reddit Linux 
Add this to your /etc/fstab file (replacing the UUID and mount point): UUID=XXXX-XXXX /mnt/exfat exfat defaults,uid=1000,gid=1000,umask=000,nofail 0 0  Key Options Explained rw: Explicitly mounts the drive as read-write. uid=1000,gid=1000: Sets the user and group owner to your user account, preventing root-only lockouts. Use the id command to check your actual UID if needed. umask=000: Sets permissions to 777 (read/write/execute for all), which is usually necessary because exFAT doesn't support native Linux permissions. nofail: Allows the system to boot even if the drive is unplugged.  
To remove the guest share that appeared all I did was remove the [Global] settings  inserted from the Samba wiki i.e.
[global]      map to guest = Bad User      log file = /var/log/samba/%m     log level = 1      server role = standalone server [guest] # This share allows anonymous (guest) access # without authentication path = /srv/samba/guest/ read only = no guest ok = yes guest only = yes  
All working correctly now. I just need to mount the board in a small plastic box and change the IP address to a static one on my daughters subnet.🙂