Thinking about it some more, it would depend very much on how ideal
their site was.
The weather in Scotland is against them but the panels shown are
rotating ones, (follow the sun) this makes a big difference. I don't
see how they could get rotating ones for that money plus they take up
lots more space.
You would get more from the same sized panel compared to a fixed one.

But the very first sentence shows the bollock brain press in the
remark about "unplugging itself from the grid"

Dunno what the new FIT payment would be, it was £0.29 for a big
installation previously. The gov, site hasn't been updated.