CONCLUSION :-
I ensured the latest Macrium image was validated so I could do crazy things to the system and revert to perfection.
I did many crazy tests, including moving pagefile.sys to HDD E:\ and removing Hiberfil.sys
The only downside was a warning from the APC battery Backup that I might lose data in the event of a prolonged mains failure and subsequent exhaustion of the Battery.
After installing and testing the operation of other software that could leave unwelcome residues upon removal,
I reverted back to perfection and chose to reconsider the big *.sys files.
My 25 GB C:\ had 8.5 GB of Free Space, and 16.5 GB Used Space.
An early Christmas present of 4 GB of RAM caused concern.
Same brand and same specification as existing memory, but very "picky" about which slot to use for one device.
Eventually it booted and started up,
but immediately I launched Windows Explorer I saw a big RED bar across C:\.
The *.sys files had each grabbed another 4 GB of HDD to match the extra RAM,
and I was down to only 0.5 GB of free space,
probably not enough to install a Patch Tuesday update and expect a reboot
Hiberfile.sys is now long gone, and Pagefile.sys is now on E:\
and my world is a good place to be in with 15.5 GB of Free Space and 9.5 GB of Used Space.
Regards
Alan