Thought I'd update everyone on this case. I have now successfully loaded 3 of the 4 machines, the last one loaded exactly as it should without incident.
I have also had an email from Riji on the customer help desk, advising my wife there is "no need to worry" as mcafee had fixed the problem.
There was no explanation as to what went wrong, no apology, and no name of the customer services director to whom I could further my complaint.
I hate to say this, but it would appear that their communication skills are far from complete in this respect, and they are not furthering the reputation of their company by ignoring my simple request for information.
Can anyone on this forum provide me with the name of a UK based manager to whom I can complain personally?