Best way to seal gap between skirting (with a round bit) and floorboards

[DonegalGhirl]

Hi,

Anyone know the most effective way to fill a gap of 2-5mm between our floorboards and skirting board, bearing in mind there is a decorative round pillar type thing that goes down to the floorboards at each side of the bay window (see photos). I’m assuming wooden beading or the like is out as it can’t be cut into a circle.

Thanks.

Decorator's caulk. There are you tube videos. But some of that wood needs sanding first.