Sorry for the late reply, alerts sent to spam - just spotted them. I have some 1.25" & 1.5" conical rubber seals, the 1.25" won't fit over the waste but the 1.5" does, my calipers also give the waste as 1.5". The seal weeped a bit so I thought I'd buy some of the 3 piece kits for future use. The waste came with the tap I was replacing. Thanks for your replies.