Well that “secrets” is a little bit of an exaggeration; it’s possibly more “paths less trodden”. Bits of Southsea you are less likely to see even as a resident.
For example, the alley between the Chinese takeaway and Sam’s Place on Grove Road South. Not exactly a public thoroughfare, but not entirely trespassing either.
And at the end of the alleyway, is the courtyard and the front doors of a few places of residence.
And around the corner, there’s an alley off Wilton Place … itself off Marmion Road.
And looking back towards Wilton Place.