want to cover ceramic floor tiles wot is best option

You can get latex from B&Q it comes as a powder you just add water and mix then pour on surface and smooth, it should look runny but will self level and will set fairly quickly over night this sounds best option as long as there is no movement on tiles

Pva then latex most building suppliers will have this like Travis Perkins. Always consult the manufacturer for advise.

I would say it all depends what your final floor covering will be. If it is carpet no need to cover the tiles, but if you need to latex i would give it a coat of Acrylic sealing agent, this stick better to tiles and does not peal, it will take approx 12 hours to set. The use the latex levelling compound. Regards, Martin Design and Tile