OP
Tile Shop
Please checkout the following advertisement.
Mapei do a product called Fuga Fresca which is basically a grout paint. Order that in 134 and it should match the existing grout:
Fuga Fresca 134 Silk Singles 160grm - https://lilleytileandstone.co.uk/fuga-fresca-134-silk-singles-160grm.html
Fuga Fresca 134 Silk Singles 160grm - https://lilleytileandstone.co.uk/fuga-fresca-134-silk-singles-160grm.html