We have a Victorian conversion - entrance and ground floor level leading to a ground floor flat which also has a lower ground level. From the ground floor common landing, there is a set of stairs leading to a first floor landing that has entrances for the first floor and top floor flat. We are having some confusion about whether this should be a two storey or a three/four storey for LACORS. The common areas are only the ground floor and first floor landing. 

Does the lower ground have an exit to open air, e.g. the building is on sloped land? Usually it's counted as a storey making it 3