The land registry title would not specify the building that was on the land. The title is to the land itself. However, if a property is converted into flats and the flats are sold then each flat would get a separate leasehold title but the freehold title would remain (with the leases noted on it). If the flats are just being rented out and have never been sold since the conversion then there would be no separate leasehold titles and therefore no note on the freehold title so you would get no clue from the title that the building had been converted into flats.