Switch off orders to Ireland (From UK)

I made a post recently regarding my customer refusing to pay a 120 euro charge on a £420 order and I've been informed by forum users that the seller is responsible for this. I had no idea, never had to pay for my customers customs charges on any other platform before.

I'm not making enough profit to justify paying this constantly so is there a way to simply disable Ireland as a selling platform? I'm only listed in the UK and I'm based in England.