Hi guys, sorry for the late response. I had actually given up on hope fixing this as had so many suggestions and tips with nothing working and thought I'd just live with the older firmware but decided to have another crack... And I've fixed it!!
So it was pretty easy and thought I'd just share in case anyone else ever stumbles across this same issue, steps as follows:
Install archived driver for Helix dating back to 2017
install line 6 updater of the same year (*note - I had to use a Windows 10 pc. Windows 11 laptop or macbook wasn't working with this and still having the same issue of driver error as the older drivers were not compatible)
Turn on Line 6 updater in offline mode, and manually install the driver (note without previous steps of installing archived driver and earlier version of line 6 updater, the helix WILL NOT register at all in Line 6 updater)
Once latest firmware installed on Helix, update to latest Helix driver and version of Line 6 Updater, and the Helix will again be picked up within Line 6 Updater.
Just to let everyone know I have just done this now and have had an initial "Boot failure, entering update mode!" message pop up on the Helix. I've just re-installed the latest firmware to the Helix again and is working perfectly.
Cheers for the help on here datacommando and silverhead!