I replaced the kitchen mixer tap, now fixed by a horshoe shaped metal flange on a threaded rod, about 4mm and a nut on a stainless steel sink and 25mm worktop. This fixing is strong enough to stop the whole unit rotating on the sink top because the tap nozzle is a very stiff to swing around when it's cold. It has a nylon seal for the base of the nozzle. The old tap had a threaded pillar and big nut, approx 1.5" diam which was more secure, also the previous nozzle wasn't so stiff.
Any ideas apart from freeing up the nozzle seal by sanding it down a bit ?
thanks
rusty