Installed a new kitchen mixer tap and sink last week.

Placed all the required rubber seals in the correct places, with the 'c' bracket clamping to the underside.

Tighten the nut as much as I could before the bloody 'c' bracket began to bend!

Still the tap block can move/twist slightly if put under a little pressure. Have noticed that after a few days of use it slowly rotates. Really annoying considering I tightened it up the best I could.

The rubber seals seems to act like a slip membrane causing it to move

Any ideas?

Thought about taking apart and applying a good bead of clear silicone. Re-assemble and allow to cure. Feels like a bodge solution to me.

Where can I buy a new 'c' bracket and does it have a specific name?