Shell, BP, Glaxo, Unilever, Brent, JCB, Ineos, Mclaren Group ( they make alot more than just cars) Rolls Royce... we have lots we sell, we just don't have a single recognised industry that you can put up and say oh yeah that's what we sell, in fact with us still haveing full access to Europe at the moment we can maybe start actually exporting at a higher percentage.
And one reason for them being in the UK is because they had access to major markets through the EU.. Most businesses will move to Europe where they still have that.. Banks, car makers and others that need the free trade.
You can take it from us here in Iceland lowering the value of the currency might be good for export but believe me when I tell you everything you need in your day to day life gets really expensive. That is if you still have a job. Wouldn´t recommend it really. Loans and payments on your houses and cars doubling. Prices in the supermarket reaching an all time high, and when the prices go to that level they will never go back to the level they were before. A normal family car here in Iceland that used to cost 1.500.000 - 2.000.000 ISK (Icelandic Krona) before the 2008 crash went to 4.000.000 - 6.000.000 ISK while you still got the same amount in your paycheck.
What save us in retrospect was that we had the EEA and could still export our products to Europe and other natural resources (electricity and hot water for house heating became really valuable). Even if things are getting better we are still not where we were before.. Not having a lot of things that other people need and no free access to other markets might turn out to be really hard. But the people who will feel it the most are the ones that vote for the Brexit..