UPVC Patio door draught

Had windows and patio doors fitted approx 3 years ago and have now found a small draught of cold air coming from the join were the base of the frame meets the concrete base it sits on. Took a look at the outside and whilst there is no obvious gap there is a small line of expanded foam of no more 3mm or 4mm and I can only assume that it has perished in places, hence the draught.

Can anyone recommend a suitable sealant that I can either place straight over the expanded foam or should I rake it out and re-seal with a silicone or mastic?

Can you not fit a length of PvC trim to the base of the door, then seal where it meets the floor with a normal kitchen sealer?

Thanks for the response, the gap I'm looking to fill is exterior so I'm not sure if your solution would be suitable.

The base of the window frame, plastic lintel sits on a concrete base which is about 5mm in height and approc 5mm in depth - it is this gap that I want to seal with a suitable filler/mortar/mastic/silicone

Well in that case I would definately mortar it in, same mix as you would pointing bricks. It shouldn't be seen unless you go low down.