Rear shocks, bottom bushes

[ihs61]

Hi

My son's 2000 W reg 1.0 Micra has just failed the mot as it requires a bottom rubber bush on the shock absorber.
Are these available on there own or do I have to buy new a full shock ? I realise that they are not megga bucks but the car has very low mileage and the shocks are spot on.

Regards Ian