We gave the walls a fresh cost of paint and used White Knight Tile and Laminate Paint from Bunnings on the tiles rather than replacing them. The tile paint has held up really well and we would definitely recommend it.
All up, it cost us around $300. We managed to replace the toilet for $150 and we were very fortunate to have a plumber friend install it for us so we saved on trades.
As we already had the wall paint from the rest of our renovations, it was just the cost of the tile paint and primer, sanding paper and fixtures upgrades.