Apple Watch Series 4 - using abroad...

Hi folks

I currently use an Apple Watch Series 2, and want to upgrade to the Series 4 GPS & Cellular.

Until recently I was based in Ireland, and I am still using an iPhone with an Irish service provides (Vodafone).

Unfortunately, the Series 4 GPS & Cellular is not currently available for sale in Ireland.

However, I'm now based in Switzerland - where the GPS & Cellular is available.

My question is this: if I buy the GPS & Cellular watch here in Switzerland, do I also need to link the watch with my Irish iPhone or is that not necessary? Will the watch operate independently of my iPhone, in terms of network connection?

Any advice would be most welcome.

Thank you

Matthew