After many years of spending hours trying to keep the bathroom/tiles to an acceptable level I find CIF and a nailbrush/toothbrush to be the best option. Believe it or not I spent 4 hours one day cleaning the grouting
Have also heard others mention the vinegar/bread soda option.
Generally find bathrooms to be a pain to keep clean.
That was me I saw it being done in "How Clean Is Your House" a few months ago, the sparkly ladies had to clean a Cave but turns out it was really a bathroom with horrible filthy tiles.
They mixed Vinegar and Baking Soda together to form a paste and left if on the grout for a while then rubbed clean and they really came up spotless.
I found Dettol very good, the green spray bottle for mould to get rid of the black around the tray at the bottom. I try the Cillit bang and to be honest did not find it great at all and I agree with Sueellen about Cif for the general maintaining of the shower
Steam cleaners are great yokes, use "neat", i.e. detatch any head and give it the full blast of steam, really deals with the greenish stuff that starts to form on the floor of shower tray, also brings up tiles and grout