I'm amazed that you could read my reply and think I'm point-scoring - I was actually just trying to have a pretty amicable chat. I suppose the heat is taking its toll, have a good weekend!
Not really. Because the date the UK was last self-sufficient is an irrelevance in the debate we should be having, but you jumped on it because you thought my apparent lack of diligence in picking a source was some sort of "gotcha", when in fact I didn't look very hard because the exact answer isn't important. All that matters is the observation that self-sufficiency in food hasn't been considered an issue for decades if not centuries - which I think we've established without too much doubt.
Similarly, the existence and size of individual solar farms is irrelevant - just single data points - but both you and Essex quote them as if they're killer arguments.
The question at issue is not "do solar farms occupy land that could otherwise be used for agriculture?" - to which the answer is obviously "yes". That's a first-order question and easy to answer.
The second-order question is "do solar farms have a
significant effect on UK food security?" To which I would answer "probably not", since the land area occupied is way less than 1%.
The third-order question is "is food security a bigger or smaller concern to the UK than climate change?".
You could go on a tangent here and observe that "well if it is, there are plenty of other ways that we could boost agricultural production" or "in the long-term, climate change will have a bigger impact on food production than the loss to solar anyway".
But none of the objectors to solar power ever work through their argument like this. They just nitpick about details or cite case-by-case examples that are easy to grasp but only address the first-order question. This is typical of the unscientific approach taken by climate sceptics and renewables obstructors. The utility and social cost of solar power in the UK is a complicated equation, with lots of terms (only one of which is the proportion of land used). Pointing to one particular solar farm and saying "look, it's [subjectively] enormous" is focusing in on one data point that doesn't even supply one of the terms of the equation.
[I will say, this debate has been useful in refining my own thinking about the way this debate is typically addressed versus what we really should be debating. So thanks for that at least.]