Don't know about this. You might want to contact Ms. Gurmeet Rai, active in Sikh conservation issues.
I think this is her contact info:
Also see http://www.sikhfoundation.org/renconv.html
Yes, that was the entire point. EU rules forbid any EU members from negotiating trade deals.
The point of leaving the EU was so the UK can negotiate its own trade deals with the US, the British Commonwealth, and the world.
If the EU had given David Cameron a bit of leeway, such as restrictions on immigration and allowance for trade deals, the UK would likely never have voted to leave the EU.
Now they will be in a world of hurt with a huge hole in their budget without the UK supporting them. They will either have to increase member contributions (for net donor members) or scrap subsidies (for net recipient members), both of which will increase infighting in the EU.