AlainK
Imperial Masterpiece
It partly depends what happens with Brexit!!
I don't think you'll have problems crossing the border in 2020, or in 2021, and the years after, whatever the results of the next general elections. I may be too optimistic, but I don't think so.
Perhaps there will be restrictions on importing/exporting plants, like there used to be about animals for the rabies, but in that case it would just be a measure of prophylaxy, which is already possible in the E.U.
For instance, I wouldn't import Ash from Britain because of the disease, but I'm certain that a government with a modicum of intelligence (French word, from Latin: intellegere=to understand) will gladly accept genetically different strains from other European nearby countries not affected with that plague.
And it might even create new jobs, or re-activate old activities like smuggling