A lot of landlords write off ECO4 the moment they realise their tenant doesn't claim a qualifying benefit like Universal Credit or Pension Credit. That's only half the picture. Every unitary authority in England and Wales can, in principle, run its own "flexible eligibility" route into ECO4 alongside the national benefits route — a route usually shortened to LA Flex.
We haven't independently confirmed that Stockton-on-Tees operates a live LA Flex Statement of Intent for landlord referrals — councils publish, update, and occasionally quietly pause these documents, and there's no central register. Before assuming a Stockton-on-Tees rental is ineligible on the benefits route alone, check with the council directly (search "Stockton-on-Tees ECO4 Statement of Intent") — the alternative route is worth £5,000–£15,000 of grant value on a single qualifying measure, so a phone call is well-spent time.
Stockton-on-Tees covers a mix of urban and rural stock, so eligibility on a given rental depends as much on the property's EPC band and heating fuel as on the Stockton-on-Tees criteria — a Victorian terrace on gas and an off-gas rural cottage produce very different funding paths.