Why wasn’t Giles at the wedding?

So, I’m rewatching Buffy and I just finished season 6. This is my absolute favorite show and I’ve seen it a bunch of times over the past 10 years so I’m a bit embarrassed it took me this long to wonder about this.

Don’t get me wrong, I LOVE the “I’d like to test that theory” moment and I’m aware Giles’ return wouldn’t hit as hard if he had just been back for the wedding. But, even though he moved to London, he was a huge part of the Scoobies’ lives for years and you’d think he’d want to be there for an occasion as momentous as watching one of the teens he’s fought alongside and seen grow up get married to the love of his life.

Plus, he could offer some great support when the wedding falls apart as the de facto father figure, which could be a nice foil to Xander’s belligerently drunk asshole father. (Especially with how many times Giles has taken issue with Xander for his dumb decisions, you just KNOW he’d be the first to try and smack some sense into him lmao)

And even if Giles genuinely couldn’t make it for some reason, why isn’t he brought up at all during the episode? Even just a side comment of “Sure wish Giles could’ve been here” or “It’s a shame Giles couldn’t make it because of (whatever reason)”. Like, nobody even mentions it. I’m just wondering what y’alls opinions are on this! (Either in-universe character explanations or writing/availability reasons)