Thanks for your prompt reply (and patience).
Device label says LS-W2.0TGL/R1-EU Nasnavigator (Version 2.83) says LS-WTGL/R1-V3 but no mention of firmware version.
LS-series-fw171_fwwin.zip download says
This software updates LS-XHL, LS-CHL, LS-WXL, LS-WSXL, LS-SL, LS-AVL, LS-VL, LS-WVL, LS-QVL, LS-XL, LS-YL, LS-WXBL series firmware to version 1.71
and I have read that LS-WXL is the correct firmware for the LS_W2.0tg
unzipped and run it still comes up with the "drive needing updating cannot be found". I have disabled firewalls and antivirus and even tried with Windows in safe mode with networking and on another PC.
So it would appear I have nowhere to go from here.