Probably boring to most people, but the saga continues. Today's update...

Our systems team have been in contact and they have confirmed when a change in booking ref: XXXXX was made, on X April 2018 an email was sent to your email address on your account.

If you feel there are other outstanding emails you were expecting to receive, then please contact me again with more details.

Despite an exhaustive explanation about my not receiving any ticket related emails for over a year, they seemed to have missed the point.