Ok so no excuses my house is dire. I am trying very, very hard to sort it out bit by bit. I am doing a bit of the approach of the glaringly obvious vile areas first and then going to try to do a thorough room by room.
First job is the grout between the tiles on the bath. Kids have used bath crayons and the once white grouting is an interesting rainbow streaked with grey soap scum kid of effect...not fetching.
I have googled. It said spray with diluted bleach and then scrub...did...no good. It said if that didn't work spray with full strength bleach...did...no good. It said if that didn't work make a paste of bicarb and leave and scrub....did...no good.
So help me get me tiles all shiny and pristine looking or else I shall get out the twink!!!! (Recommended by ds not google)
Like you I found bleach not that great, even with a toothbrush so didn't expect much from a special brush but thought I'd give it a go... Lakeland Tile & Grout Brush is amazing! I mainly just used it with a little water & it got rid of most of the scum, mildew & other yuckyness. The tiles also came up looking like new. Just don't rub too hard! Then, for v stubborn areas that weren't coming up as white as the rest, I applied Domestos Grot Buster (looks like a toilet cleaner bottle, black) as per instructions, then scrubbed with the brush before cleaning off. You may want to use an old towel to protect the bath first, especially if it's an enamel one, as although the grot buster 'sticks' more than other cleaning products, it does still run down a little. I had planned to get a grouting pen after but didn't even need it after that.
I found bicarb on a microfiber cloth quite good. And one of those "for delicate surfaces" scrubby pads.
In certain areas I used muriatic acid, but lost my nerve when I discovered I didn't cause injury/accident quite by chance. (you have to either add the acid to the water, or the other way around, and if you get it the wrong way round....hells bells!)
I aslo found that single attacks did not completly resolve the situation. It was an ongoing job, redoing already done bits regularly, that got things to a decent result.
But wait! You are in the UK? Don't the shops there have those magical grout pens that make everything wonderful again in a jiffy ?
I heard about them, but sadly in Italy magic grout pens must be banned by the pope or something, cos shopkeeps looked at me like I was on acid or something. Just like they did when I was trawling around looking for a paint stick. And paint for tiles (ten years ago).
I don't have any experience of bath crayons, but I use the spray anti mould Dettol bleach for the bathroom that comes in a lime green spray bottle - it's about £2 in Home and Bargain and it brings up all my shower grout pristine white without any scrubbing at all. This one.
seems like it's only Asda who do it (also Ocado), and my nearest Asda is 45 minutes away . But, I think Ocado deliver here (rather than Waitrose), so maybe i'll be forced to splurge on groceries in the next couple of weeks . Thanks crunchingicicles