Which grout for regrouting splashback?

[RT]

Hi all, hope your all having a fabulous evening

So I’m doing a DIY to the kitchen splash back by removing the grout and regrouting. If this still looks unfortunate, then I’ll take out the tiles, repair the wall, and put new tiles in. 

I would like to know what grout at Bunnings I should use?  Bought the Dunlop coloured flexible grout but after some research it appears I need coloured sanded grout because some of the grout lines are more than 8mm. Which product would be suitable to achieve a solid regrout? Pictures below for reference