I heard from someone that works in the clothing industry that there are strong links between Italy and China, i.e. there are lots of chinese workers in Italy working in the textile industry. When the talk of the first lockdown was spreading, a lot of people got out and went to Italy. I think this is supported by the fact that the first outbreak in Italy occured in a lot of small towns and away from big cities, typical locations for industrial jobs.
"More than 50% of fish caught by British boats end up elsewhere in the EU". A 47km traffic jam isn't going to help getting fresh fish exported either, that's the least of their worries.
What's most terrifying is the knock on affects of one of the largest economies on the planet going into reverse for 5+ years.