Owning your own home

I've just remortaged my place and have received an email from the solictors saying:

I am writing to you as we have received a requisition from the Land Registry that your property is registered as 18 XXXXXX Road whereas the mortgage offer is in the address of 18B XXXXX Road.

Are you able to confirm which address is correct? Please note if you do wish for us to amend the address, we would just require your consent to do us which we are able to accept via return of this e-mail.

The property is two flats in a house. Mine is the upstairs flat, hence the B. I own a share of the freehold of the building (together with downstairs) and the flat has a lease from that.

Looking at the land registry website I can see that there are records for 18 XXXXXX Road and 18A XXXXXX Road. I assume the A is the downstairs flat.

For other flats on the road there appears to be entries for the whole property and the flats, e.g. 14,14A and 14B

Would there be any issues that anyone is aware of in changing from 18 to 18B. Should an element of this be left as 18 to reflect the freehold?

I will ask the solicitors this but they are the free ones that came with the mortgage so no idea how good they are or otherwise.

Cheers