I need to stick an acetal/perspex splashback behind my lavatory. Basically I want to just knock the old tiles off, sand one side of the acetal to give it a key and then apply the adhesive and put the acetal in place to cure. Not keen on removing the old tile adhesive as its an awkward working position. So the adhesive needs good gap and strength properties on acetal. What would be the best adhesive for this task? Polyurethane based? I thought of using a couple of tubes of no more nails? Contact adhesive might not have the gap requirements for the old tile adhesive surface.