Apple Watch Series 3 - cellular with plusnet

[#1]

The new Apple Watch (series 3) has been announced with its own built in sim. Currently only EE are listed as only UK network supporting this.
Does this mean Plusnet will work with it too as it uses the EE network?

[#2]

http://www.macworld.co.uk/news/apple/apple-watch-series-3-release-date-price-tech-specs-3647016/

 EE, the exclusive data providers for the Series 3

No.

[#3]

Any chance that plusnet are going to offer it?

[#4]

Unlikely as it probably comes under the category of parts which the EE sub vendors can't offer such as 800MHz G4

[#5]

I would have thought it may be possible, but couldn't be certain.

In my last company we used a business telecom provider, and we had access to their systems which in turn had access to the systems of the physical network.

I would assume PlusNet have access to an EE system, to manage their accounts. I would have thought it would just be a case of activating the IMSI of the watch?

But don't take my word for it, and I suspect it could be more complicated than that.

EDIT: Thanks @Oldjim, I didn't realise frequencies would come into it.

[#6]

It won't be exclusive then