All EVs will include an electric battery. Its not like the battery you have in your car today, its a large part of the assembly, as I'm sure you are all aware. If all the batteries are made somewhere else, and it costs a huge amount to import them, why would you go about setting up a factory in the UK to build your EV? Well, you wouldn't. Hence, the absence of a viable battery source in this country will depress the motor industry and potentially lead to its demise.
As for your "cabs" M0nica. The only large scale manufacturer of HGVs in the UK now is DAF. 20-60 cabs a day would be right as they manufacture about 15,000 trucks a year. Great. Until you realise that Sweden alone manufacture double that number and about half a million trucks are manufactured in the EU in a year.
Its completely wrong to say that Brexit has made no difference. My last job was in an organisation supplying to HGVs, an organisation that doesn't exist in the UK any more because Brexit made it uneconomical to be here and to export as needed.