I think that would be an excessively generous interpretation. The overseas assets in question are most likely held in low or no tax jurisdictions. It's not really double tax if you are just topping up from 0-5% to the UK's already very low CGT rates!
Is it then to prevent double taxation?
If it's one of those cases of leaving assets where there's barely any tax then I feel less sympathetic once again.
Companies are however doing this all the time...