Hi, I've new 600mm towel rails that require smaller spaced tile holes than the existing older and larger holes present. The backing plate will cover the old holes if I'm able to attach it quite close to the old holes. I'm unsure about whether to fill the old holes and then drill new ones in the position shown in the pic, or should I try to use one old hole, drill only one new one above and then seal other old hole and hope it isn't visible. My worry is how close can you drill tile holes before risking weakening the structure. New holes will be 5mm. The old ones are much larger. Many thanks for your advise.
