Start with the premise that a “safe zone” for social nationalism is created, perhaps in the South West of the UK. The zone might centre on a suitable country house or other large building, on a farm, or on a hamlet or other cluster of houses. In that central area, almost everyone would be a social nationalist. Further around that centre there would be villages and small towns where many would support the project. Further out yet, another circle where the influence of social nationalism would be less concentrated, less powerful, though still stronger than in the country as a whole.
News about the germinal ethnostate would spread. No doubt most of the reportage from mainstream media would be hostile, but no matter. People living far and wide would hear about the project and would come to visit the safe zone and then, in many cases, to relocate there, to live in the villages or small towns of the region. Even if only 1 in 1,000 in the general UK population did that, the safe zone might eventually attract thousands and even tens of thousands of suitable people.
The political effect of the resettlement would be felt in elections for local councils as well as for the Westminster seat or seats for the area. The effect of even 5,000 dedicated social nationalists voting en bloc cannot be underestimated. 1 in 1,000 of the UK adult population would in fact number about 50,000. This is not a mere pipe-dream: it is feasible; it could work.
Another important factor in the proposed resettlement is that, unlike the usual situation at present in the UK, in the posited safe zone, social nationalists would not be a small fringe or marginalized group, but a significant minority which might become an unstoppable majority in time. The consequential effects on the rest of the UK would be huge.