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This is down to the Government's disastrous policy of permitting change of use from commercial to residential. It's not specific to the property in question. See here:
A mixed use comprising an A1 or A2 use and up to two flats may also be permitted subject to meeting certain conditions
https://www.planningportal.co.uk/info/200130/common_projects/9/change_of_use/2
How likely it is to happen depends entirely on whether the owners of the property want to make this conversion, and on whether they can afford it. You should get in touch with them (if you know/know how to find out who they are) and ask them.
I'm considering buying a house but the property behind (that has access through an alleyway next to the house) has permitted development rights for conversion from a commercial unit to 2 large residential units. As I understand that means there's not been a planning application (there's none registered) but development could go ahead without planning permission. It's currently a single storey office block. How's that possible and how can I find out how likely it is to happen? The property is in a conservation area.