I will have to pay more attention to the message boards. I complained to Ancestry about this shambles in September and, after some to-ing and fro-ing received this reply.
"Thank you for contacting Ancestry.co.uk regarding the problems you have encountered in our database, 'London, England, Electoral Registers, 1847-1965'.

It will not be necessary for your to provide any further information documenting the record problems you have found. We appreciate your letting us know of these issues and for providing the attachment.

Thank you for your error report. The problem has been reported to our developers. Feedback from you, our valued customer, helps us correct errors and improve the web site. Your patience and efforts to assist us in this matter are appreciated.

Please understand that fixes to errors on Ancestry are posted firstly in the order of those which affect the greatest number of users, and thereafter in the order in which they are reported. For this reason, fixes for some errors may take longer than others to be posted. We appreciate your patience."

I fail to see how OCR alone can be blamed for the mess. It only reads what it is told to. The registers are in a number of formats and each needs to be catered for. Even then, different results are given for registers containing identical information in the same format.