They'd already had more than one rehearsal, the first with W&C, so this thing with Welby was something else and not a rehearsal. It wouldn't be normal for the AoC to be with them on his own, "just the three of us" as she said in Porker. No witnesses, why?
Certainly not your normal royal wedding rehersal, it's all very strange and I think it was something else. There have been rumours that the Snarkles had a ceremony in Botswana, and this could be plausible as she wanted to nail Noballs down under the stars.
The secret event with Welby could have been something to do with this, or it could have been an attempt to "shrive and purify" her soul - in which case Wobblin' failed miserably.
Maybe an exorcism??
Nil points again Welby.
All gossip, no idea what went on, but HM will have known about it and it's odd and secretive.