How big a system will a Tewin Road unit take?

It depends on the qualifying roof slope rather than the building footprint, which is why we survey before sizing. For scale, marketing particulars for the Tewin Court terraces give unit sizes of roughly 4,900 to 9,900 sq ft, and the newer Tewin Road warehouses were marketed at roughly 13,400 to 39,900 sq ft for B2 general industrial, B8 storage and distribution and E(g)(iii) light industrial use. A roof in that range is firmly past the G98 threshold, so the grid application is a G99 approved before installation, and anything above 50 kWp sits outside the MCS scheme scope — both of which change the programme, not just the price.