What counts as limited infilling within a group of houses?

Two undefined words doing all the work

How many houses make a group, and how big a gap can be filled before it stops being limited, are both matters of judgement on the facts. There is no number in the framework and no distance.

The practical consequence is that this route is strongest where the gap is obvious: a single missing plot in an otherwise continuous frontage, with development on both sides and a clear building line to follow.

The pinch point for self-build

Multi-plot self-build schemes on an infill frontage sit naturally within this route, and it is a well-trodden version of it. But the more plots you add, the harder 'limited' becomes to argue, and at some point the scheme reads as an extension to the village rather than as filling a gap.

It works in the Green Belt too, differently

There is a separate route for limited infilling in villages lying within the Green Belt, and it is by far the cleanest route available there. It carries no unmet need test, no Golden Rules and no grey belt assessment. Where the facts fit, it is much easier than the alternatives.