This is somewhat repetition but some just don't get it.
1) The UK is the 5th largest economy in the world.
2) India is the 7th largest economy in the world.
3) India is an historic and natural trading partner for the UK.
4) Australia is also a large economy and an historic and natural trading partner with the UK.
5) Despite the importance of strong trade relationships with the UK, the EU will not let the UK give favored trade status to any non-EU country, like India and Australia.
6) If the EU puts up major trade barriers (tariffs) for trade with the UK, the EU members will lose the market of the fifth largest economy in the world, while the UK gains India and Australia, etc.
7) I am buying Pounds now just like I bought the Euro at 88 US cents. It will make traveling to the UK affordable again. That is a benefit of the possible reduction in the value of the Pound. It will also make UK goods more affordable and thus more popular worldwide. Unfortunately, the Pound will recover at least most of its value. The world craves stable currencies and the Pound Sterling has been one of the best for centuries.
Let everyone else panic. Things will level out. Both Europe and the UK need each other. They will work it out in as mutually beneficial a way as possible. And remember, this separation is a long process; at least 2 years, maybe more.