Is it possible to buy an UK Nintendo eShop card with a non-UK PayPal account?

Solution 1:

From the Terms and Conditions on www.paypal-gifts.com

• If you are buying an item, unless otherwise agreed with the Retailer:
  • you must pay PayPal Digital Gifts for the item using a valid PayPal account with a registered address in the UK; and
  • your purchase of the item will not complete until after your payment to PayPal Digital Gifts has completely cleared.

To answer your question: No it is not possible to buy an UK Nintendo eShop card without a valid UK Paypal Account on paypal-gifts as long as the retailer dont say so.

Here's a list of retailers (in europe) ordered by country where you could buy eShop cards but i dont know if you'll find UK cards there. I'm sorry but I wont tell you were exactly you can buy what you're looking for because questions like "where can i buy XYZ" are not allowed neither recommendations are but Yes you can find what you're looking for if you take your time searching for it.