You only ever pay VAT once, that from experience is in the country where you have the CD's, Merchandise, etc., made. VAT is the EU wide tax that basically pays for the EU.

After leaving the EU the UK will be free to do one of three things with VAT.

1. They can leave it exactly as it currently stands and use the revenue raised to pay all former existing subsidies formerly received from the EU and pocket the surplus [The UK is the EU's second largest net-contributor after Germany] to squander as they see fit.

2. They can reduce the level of VAT wholesale or on whatever selected items they see fit thus reducing the price of many things but still taking in enough to pay former subsidies.

3. They could abolish it altogether, then of course bands, musicians, performers would have to render unto Caeser the things that are Caeser's. This of course would only be on what they decided to take with them and they would not have paid any form of VAT on the items in the UK so they would have been cheaper to make in the first place.

As with all things in life it is usually a case of "swings and round-abouts".

Don't know that many bands now that do actually make money lugging vast numbers of CDs and merchandise about. For the music, streaming and downloading seems to be more the norm.