We have the titled tap pictured here and the part above the bench wobbles. Having gained access to the underside it appears that the design is such that the whole assembly fits to the bench through what I would class as a kitchen sink 'waste outlet'. This part is rigidly fixed through the bench and does not move when the part above the bench is wobbled. The two inlet pipes can however be felt moving in the centre of the 'waste outlet'. I can only assume that the top part is attached to the 'waste outlet' via an o ring or similar, and perhaps is somehow screwed. Does anybody have any ideas, please?