Homes in SA11 sell for a median of £150,000 across 614 sales over two years (HM Land Registry), which is -9% against the Neath Port Talbot median of £165,000. Set against the local average rent of £689 a month (ONS), that implies a 5.5% gross yield here versus 5% for Neath Port Talbot as a whole.
Rents are published per district, not per postcode, so the yield above applies the Neath Port Talbot average rent to SA11 prices. It's the right way to compare postcodes on entry price, but rents do vary street by street, and gross yield ignores costs, voids and mortgage interest.
SA11 averages tell you where to look, not whether one particular flat stacks up. Paste a listing and gemhome runs the actual numbers: yield, cash flow, the lender stress test, EPC work and what the public records say about that specific address.
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