OP:

You are not clear on what you are asking IMO

Is this relative bringing something with them from the UK that you cannot get here in the USA? Or are you trying to get something for them from HERE that they typically cannot get in the UK?

I thought the OP was quite clear, he has a relative coming from the UK who could bring spirits that are not available here in the US.

OP - have your relative bring a bottle or two of Yamazaki Distiller’s Reserve Whisky. It’s not sold in the US, and is quite an excellent single malt (no age statement, however). Classically Yamazaki smooth, with notes of fruit.