Thanks for the reply Burr, I was hoping you'd help.

However, the first choice didn't work. It tells "Verification 98% complete. Windows Resource Protection found corrupt files but was unable to fix some of them".

Details are included in the CBS.Log windir\Logs\CBS\CBS.LOG.

I get denied access when I try to view the 38MB file.

The second choice was more hopeful. The downloaded Updates history had reset and indeed tells me to 'Check for Updates on your computer. When I click the update tab it tells me 'Install new Windows Update software'.
On clicking the update tab I now get a 'Windows could not search for new updates' with an error code: 8007000B.
The Try again tab loops the process again.

Many thanks for giving your time on this issue.