I just came across this posting. I am based in the Republic of Ireland and also decided that it was too much trouble and effort to supply Great Britain ( that's England, Scotland & Wales).
Personally, I can't see how another country can enforce Vat (tax) collection and remittance when I am in another juristiction.
I did a little research and came across an app that might be of help.
I am still looking into it and if anyone else has any ideas, then I am all ears.
I'd love to share our Brexit Guide for Shopify merchants with you. Even though it's primarily aimed at Shopify stores based in the EU, I believe it will help you understand the situation a little better.
If you have any questions regarding invoicing, feel free to get in touch with us at email@example.com.
All the best,
- Max from Sufio