I contacted CW management via email and this is what I got back about the release of the dvd
Thank you for your email.
In reply to your query, the new Ancient Land” DVD will be available towards the end of January 2019 generally in the US & Ireland and may be purchased in shops and online via our online shop: HERE. It will be released “Region Free” Further details about the release will be announced in the newsletter and on the website early in the new year.
Kind regards
John Flanagan
Celtic Woman
But he didn't answer about a Bluray vers so who knows
At the castle they explicitly stated there would be a Blu-ray release of Ancient Land. Of course that may not happen at the same times at the general DVD release.