Noisy rear shocks?

Dunno if this is a problem perculiar to my car ...

The plastic rear shocker dust sleeve/cover is now detached from the shock itself and makes a shocking racket when I drive over bumps when it crashes down. Being cheap and nasty plastic it makes a right racket and is driving me nuts.

Nothing wrong with the shock itself, just that ruddy cover ... so ... being a tight sod I came up with a cheap fix;

I've used a spare bit of 22mm foam pipe insulation - cut a half inch piece and fitted it under the top of the plastic shock sleeve, so when I go over a bump now the foam insulation stops it crashing down on the lower part of the shock body.

Simples