Lorne Michaels has done multiple comedy shows for Canadian and US audiences. There’s no reason to believe that this version of SNL won’t be focused on the UK.

They likely aren’t bringing sketches from the US show over just like SNL didn’t do SCTV bits. The only constant I would expect is “Weekend Update” which is in the middle of the show and is topical news jokes. That bit will only work if it is centered on UK politics and culture.