Who wants a trade deal with the US? Certainly not the vast majority of the supporters of Brexit. A deal with the former Dominions would be welcome and with a great many other places, but not with the US. The prime minister may think differently, but if he does, he does not represent the people who voted to leave the EU.
Who wants a trade deal with the US? Well our democratically elected government. That's why they are trying to get one.
Who wants a trade deal with "the dominions"? Brexiters who live in the past and think the commonwealth will save all.
But they won't. India will do us a trade deal at the cost of allowing visa free access to this country for its citizens. That's their price. They will not back down. Their price is generally considered unacceptable to many in the UK.
new Zealand will do a deal cos they want to flood the UK with their lamb thus destroying British sheep farmers. That's their price.
Australia frankly don't care. They are more interested in pursuing more local markets. Cos that's the thing with global trade. It's global but actually the most important trade is the trade on your doorstep, not the trade thousands of miles away.
Always, always, ALWAYS remember trade deals run two ways. Many Brexiters cry "the Commonwealth!" in their desire to get away from the EU but trade deals don't happen out of the good of a country's heart. No one in Canada is going "let's do a trade deal to help out the UK.". No. They are going "What can we get out of the UK that benefits us?". And ask yourself why India and Australia would prioritise us over trade deals with the far bigger EU? Hint: they won't.
Besides, the trade they can offer is still puny compared to what's on our doorstep. The best trade deal we can do for this country is the one we can do with the EU.
By the way, calling them "dominions" might not go down well with them... It's a bit, you know, patronising...