.........and finally a reply appeared which stated the following
"Dear Mrs Meek
Thank you for your recent enquiry.
We have checked the pages at the index reference 1985 September 14 1583 & 1584.
The entry for George Twigg appears on page 1584.
We can only advise that an error was made at the time the indexes were compiled which shows the name on both page 1583 & 1584.
We hope this information helps.
Regards"
So nothing untoward, just human error.
Thanks everyone for your input.
Sally