Suziewoozie, agreed, whether it's an HMO has nothing, at all, to do with the landlord living there.
cornishpatsy, the fire risk is far greater when there are tenants/lodgers as they have exclusive use of their rooms. They may well install fridges, mini cookers, toasters etc. rather than use the shared kitchen so much.
Older terraced houses often have gaps, where fire can easily spread, between floors or attics - especially if there has been movement or settlement over time. There may have been dodgy repairs and building work too.
My son bought a converted first floor flat in (apparently) decent condition. When he removed the kitchen units, the backs were very charred, floorboards/joists burnt through and smoke damage up the walls.
A family of mice were there too. A quick repaint had completely disguised the damage - and yes, next door had a fire some years previously!