You could also try using LTP products for this.
LTP spot stain remover and LTP fullers earth, these are designed for grease stains etc.
Tile giant will be able to get these or might even have them in stock..
LTP Spot Stain Remover
Description: LTP Spot Stain Remover is effective at removing the majority of mineral oil and cooking oil stains (including oil spatters). Suitable for use on quarry tiles, terracotta, limestone, bricks, cement and paving. Combine with LTP Fullers Earth to help remove older cooking oil stains.
Tips: Pick this product if you have spot stains from hot oil and other absorbed domestic spillages....
Technical Data Sheet (PDF)
LTP Fullers Earth
Description: LTP Fullers Earth is an ultra-absorbent stain remover for all greasy stains (oil, grease, make-up, sebum etc.). For use on fabrics, leather, porous floors, stone, terracotta and wood. For stubborn stains on flooring combine with LTP Spot Stain Remover.
Tips: Pick this product if you have spot stains from hot oil and other absorbed domestic spillages.