It's affectionately known as the Worp Drive switch

The kick down isn't really the issue. If I shift down manually then it's all normal but the bogging down does happen; not always, just sometimes.

It could be the IC Pump but it might also need a throttle re-set. I do a lot of city driving and I tend not to mash it so the fly by wire learns my driving style and the gearbox responds accordingly.

That's also a possibility.

BTW I also like the photo with the top down