BOAC, many thanks.
Completed the "remove Office xxx" but then it hung again but then with a bit more digging found this:-
"Click on Start > run > Browse to the CD and select the setup.exe > Click on Ok > Type cdcache=0 after that setup.exe in the run window and then click on Ok again and and check if Office 2003 installs without any issues"
Then install ran ok - happy days!