For sure Simon, the VAT system is largely simple and effective. And the changes going on in the EU from 1st July 2021 will not have any material effect on UK businesses.
My primary concern is that EU customers from 1st January 2021 will be charged VAT locally at the point of import/delivery - and whilst it doesn't really matter where the VAT is paid, the extra friction and likely 'fees and disbursements' that will be charged to collect the VAT will be a PITA for EU customers buying from the UK.
Example (assuming exchange rate 1.11)
UK company selling a £30 thing to an German customer before 1st Jan 2021:
£36.00 (£30.00+VAT) paid by customer to UK company
£6.00 VAT forwarded by UK company to tresurary
thing costs customer ~€39.96
UK company selling a £30 thing to an EU customer on/after 1st Jan 2021:
£30.00 paid by German customer to UK company
£5.70 VAT (equivalent at some likely rubbish exchange rate) paid by German customer to German treasury via postal service or courier.
€6.00+ paid by German customer to postal service or courier for the service..
thing costs customer €33.30+€6.33+€6.00=~€45.63
On top of the extra cost for the customer there will likely be another day added to the delivery cycle and inconvience to the customer.
Can any EU forum members contribute examples of buying items from outside the EU, in particular the costs and delays incurred??