This refers to the Local Government Ombudsman's addition of the words Significant/Material to the level of injustice a complainant must suffer before they investigate.
The 1974 Local Government Act does not include any such qualifying words.
Therefore, the LGO have fettered themselves by the introduction of said qualifying words and are now refusing to do their public duty and investigate complaints of injustice suffered through maladministration.
This is what Lord Denning, Master of the Rolls, had to say on the matter in HTV Ltd v Price Commission (1976)
“A public body which is entrusted by Parliament with the exercise of powers for the public good cannot fetter itself in the exercise of them. It cannot be estopped from doing its public duty.