I would say it's deemed declarable import to UK Customs on arrival from France. As far as I am aware, there is no bonded in transit to other EU country via UK regeme.it would be impossible to check or control that no duty free alcohol goods were offloaded in GB before export to Ireland.
In Ireland, the customs then treat as import from UK so apply basic limit, not intra EU limit, of 60l of wine (deemed personal allowance)
Ex France with a boot load of wine is best direct sailing to Ireland.