How to get incorrect information changed on a land registration document

The registration document for my son's flat has the wrong address for where he is resident. The address next door to his flat has been entered. Although the document does list the address being registered correctly we have been trying to get the residency address corrected via the conveyencing solicitor and our own emails since April 2023.
The solicitor raised an application to HMLR on the 20th March 2023. HMLR ref. N309FXS. We have received no action from HMLR at all despite it now being over 4 months later, chases by the solicitor and a request we raised a month ago.

Could anyone advise how we can get some action on these sorts of changes and or an escalation route.

Joan - the application was completed on 8th July and the register updated. The conveyancer was notified also and hopefully they can confirm that for you both.
I'm sorry for the initial delay re completing the application