Dom Gregory Dix was an Anglo-Catholic and a member of the Church of England, not a Lutheran. He believed in the real presence, transubstantiation, and the Sacrifice of the Mass. He also personally used the Roman (Tridentine) Missal. His theology of the liturgy is totally opposed to that of Luther. He also saw the evolution of the liturgy as properly involving an organic development, and would have been horrified by the haphazard manner in which the 'reform' of the liturgy was carried out by the Consilium.
Modern Lutheran services have been influenced by ecumenism and therefore have adapted somewhat to the Mass, however, it is obvious to anyone who knows about the Catholic doctrine on the sacrifice of the Mass that the Lutheran service is not a Mass in this sense.
Upon consideration this statement is too much. I have no reason to believe that he held to transubstantiation, though others of the Anglo-Catholic party did and do. The other two statements are well-founded.