Hi

It depends on whether you want off-grid or on-grid solar installation, but looking at the panel array sizing, I’m guessing on-grid.

For on-grid installations, you have to be MCS-accredited and sign-off on the work before being allowed to self-generate and export.

No MCS installer will sign off legal paperwork and accept legal liabilities for equipment he didn’t source himself.

This is a BRE regulation.