I am about to fit a Watersmith mono tap to a stainless sink. There is a triangular plastic spacer supplied which the instructions say is for use if the sink is less than 35mm thick. Mine obviously is thinner than this but the spacer will not sit flat under the sink due to the shape of the sink in this area. The thread on the fixing rod is threaded over its full length so I am not sure why the spacer is required. The only thing I can think of is that it provides rigidity around this area for thin sinks. If this is the case, I can trim it down slightly to fit within the contours of the sink. Any advice appreciated.