I’m thinking of buying a used car from a private seller, I checked the mot history and the following were advisories and just wondered if they were major or may affect the car in future. The car passed last mot so obviously been fixed

• Nearside Outer Drive shaft joint constant velocity boot split or insecure, no longer prevents the ingress of dirt (6.1.7 (g) (ii))
• offside front outer cv boot slightly leaking grease (clip)

As advisories there's no requirement to fix them to pass the MOT. I'd assume they haven't been fixed and will need doing in the future, unless the vendor can prove otherwise.

Were the advisories on the most recent MoT (which would still be a pass) or on previous tests?

If not on the most recent, it's a fair assumption that they've been fixed, athough there's a chance that they might just have been missed by the tester.

Fixed or not, its a fair bet the CV joint is compromised.

If dirt got in, was it thoroughly removed before the boot was replaced?

Oh really?

HOW exactly?

They can go on like that for ages, but worth pricing CV joint replacement to weigh in your deliberations.