That’s exactly what it is yeah. 22 years (or 20 for the boy) before they’ll be eligible for parole. If they’re deemed to still be a risk to the public then they won’t be released.
The UK doesn’t do life sentences with no eligibility for parole. Every sentence will include eligibility for parole, with the maximum period for eligibility being around 25 years. But obviously there are still plenty of prisoners who don’t get parole and spend their entire life behind bars.