That is a hard one with those tiles. I would have to think if you did a white, it would kind of work with the colour of your tiles. At the end of the day, they do need to be replaces, but as you said, due to budgeting reasons, you cannot, I can pass on this photo of a nice bathroom with those tiles for you though for inspiration... : )

Thanks Hanna, it's as green as I could achieve with the look I wanted. The mirror is the previous one with a new surround and the tiles are by Porcelanosa. The towel rail, light fittings, shower enclosure, timber vanity and the grates (shower and floor) are Australian made. The imported granite on the vanity top was cut to size and fitted locally.

If I walked into a bathroom that had painted tiles and I didn't have the money to repair it, or I liked the original yellow, I'd be dark. Once you paint it, the tiles will definitely need replacing at some stage. At work I always say, will your quick fix make more work in the long run. Change the taps to chrome(stainless is too expensive) and leave it. It's a clean functioning space that will not turn anyone off.

Sounds like a very stressful situation! If there is absolutely no way the builder will allow you to change things (even if they did, I imagine they would ask you to foot the entire bill of pulling the tiles down and replacing all water proofing in addition to new tiles), I can make a few suggestions for improvement. Firstly I would suggest replacing the tiles above the vanity with a white mosaic, a patterned or a textured feature tile/strip. You could also use this same tile to replace the vertical feature in the shower. There are some beautiful shapes and sizes available to choose from. Secondly I would address the grout situation in this way: Floor - dark colour grout & Walls - Light colour grout. Lastly if it does not prove too difficult or expensive, maybe replace the tiles below the vanity with a plain white tile (could be similar size). Good luck and I am sure once you have a lovely mirror up and some crisp white towels, it will look just wonderful.