I've tried removing it in the past with grout files etc but they are useless. Unless I'm doing it wrong (again)........
Is the shower on a combination boiler system ? Great to see a new shower fitted instead of messing around with repairing the existing unit. have cleaned grout with fine sand paper folded around a credit card,cut the sand paper to same size of credit card then gently rub the grout line top surface till its clean,same process can be used to re shape existing hardened grout where to much has been applied.
If you do decide to renew grout at some stage, forget using a grout file, will take a lifetime at least Multi tool with carbide blade is your weapon of choice. 2/3 hours and all removed. Need to remove full depth of grout before cleaning and applying new grout They do sell electric grout removal tools but purchase a multi tool (if you haven’t got one), so many more uses
Well Rs, I’m The Man of the House and totally agree with Your Lady .... The Dettol spray is by far the best on the market, and I’ve tried plenty Great product that just works