FWIW Ukraine is not in the EU.

It's not. But it's a huge agricultural country the size of France, located in a different area.

Yes, that was sarcasm.

It's also the middle of a war zone. Why is it easier to get tomatoes there than the UK? Why can't the UK use its massive GDP advantage to get them?

I had some lovely tomatoes last night. I expect it's just that Ukranian newspapers have better things to discuss than cucumber shortages, so there's no panic buying.