The context is related to conversion of old style bedsits to modern legit bedsits, the latter needing their own separate bathroom and kitchen areas.
As it's an old house and on the second storey, I see no need to have wheelchair accessibility in this case.
The reason that this is being considered in so tight as space is that all the intended space of the renovated unit would be within a rear extension.
Looking at the space and mentally moving the items around, I think that it is PHYSICALLY possible.
But the question here is, is it allowable within building regulations to have things so tight ?