Sorry Old Blue but IMO Wig & Pen is not in Old Portsmouth.
Old Portsmouth is the tight area around the Cathedral, the top North limit being Duke of Buckingham, and East the Pembroke
South & West limits are the water of the harbour
Nor is it in Southsea Central, if anywhere it is Southsea West, which does not exist, it really could just about fit into "Southsea"
Given as the postal address is Landport Terrace I suggest Landport is the location for this pub, even though it is on the very extreme edge
The same applies to the Horshoe which is now a block of flats