The arrogant may government did not approach the USA for a deal, when they realize they are not going back to EU, they will approach the USA. And trump will reward their independence... the poles are going to change their minds when they are threatened by Belgium.
Now whatever be the actual health risks IF ANY of these is secondary to public perception. The UK public right now perceives American poultry, beef and eggs as something they don't want imported. This is against what American farmers (naturally) want and this will scuttle any trade deal
NEXT, The UK has a bank surcharge -- an additional tax. This is to be removed as per US trade deal. The Brexiters wants to remove a tax on banks - makes you wonder who the charge of "bank owned" should be directed against.
When the Hard Brexit happens - if it happens, the UK will approach the USA and the USA will tell the UK "scrap all your regulations and follow mine. You have zero leverage against me and I have all the cards" - and that's normal in trade talks
On the contrary to Brussels (btw, you know there are also differences in opinion between Belgium and the EU, right?) dictating terms - thanks to the linkage between Morawiecki-Orban and now Selvini, the Visegrad point of view will be joined with Italian as well to counter the Franco-German axis. And the UK was a proponent of LGBTQ in the EU, remember, so its' leaving is only going to weaken the pro-gay lobby