Front upper wishbone dust cover replacement

[MkGriff]

Hi All,
My 98 Griff had its first MOT failure, due to the dust covers staring to perish - can't complain!
I tried the search, as I'm sure that this will have been discussed many times previously - but couldn't find anything relevant.
Are these well known parts and readily available please?
Has anyone had a go at replacing them - and if so, could you recommend an appropriate ball joint splitter?
thanks in advance.

[Adrian@]

Buy silicone versions (measure the size) EVEN if you replaced the joint you would need to replace the new ones with silicone versions. A@

[phillpot]

I'd replace the complete ball joints, reputable brand like Lemforder should have decent quality rubber bits.