Thanks I've got the fugi kit....Not tried it yet. I'm guessing its best to keep the joint grout free before siliconing as with corners and around the bath? If so it will be "fun" as the "pro tiler" who did part of the job made a pigs ear of the cuts and left me with a gap up to 7mm in one place.
As I have this problem could I grout first then Silicon a fine colour matched bead over the grout to the window. I don't fancy a fat Silicon bead if possible. Many thanks 🙂