Regarding sending to EU.

A couple of Years ago EU made a VAT wall. If a citizen inside EU buy from outside, they are to pay VAT of post plus the value of the goods.
This can be done in two ways. One is to pay via the customs services. This by getting a VAT note to declare before the goods are sent to receiver.
The other is to pay to the seller, Who then pay to a IOSS central, and get a IOSS number, to put on the packet.
In the last case, sending from UK to EU is swift. Although it give the seller more work.

OFC there's always possibilities for error. I bought a packet, via ebay, last year. Paid VAT via them, and had a lot of troubles.
Seller had forgotten to declare or label with the IOSS number. So after nearly three months, i had to file a refund. - This after hours of calling and writing back and forth...

As a customer, from Denmark, an example.

You buy a sporran for £80, and another £20 post.

If the IOSS system is used, the calc would be:
(£80 + £20) + 25% VAT = £125 total

If no IOSS used:
((£80 + £20) + 25%) + declaration at approx. £17 so = £142 total

If no IOSS via ebay:
((£80 +£20) + 25%) plus another 25% VAT and £17 declaration. So = £173,25

And in the last case you can TRY to get ebay to pay the 25% VAT back (they have added). (Good luck!)

Yeah. If something can be difficult, it seems it shall be! Hmm...