The website explains what it means very thoroughly:
Dearmer Groups are for ordinands currently in training who aspire to membership of the Society of Catholic Priests (SCP) and who are in sympathy with the principles of membership.Those living under priestly orders experience both the joy and privilege of ordained ministry and also the sacrifice that ordination brings.At a time of great change and stress within the national and world Church, many priests are both at risk of isolation and loneliness, and also find themselves challenged by the changing expectations of the church.Membership of SCP offers collegiality, encouragement and support in the face of such conditions.Aspirants are encouraged to adopt the rule of life of the Society, that isEucharistic centred spiritualityto say the Daily Officeto consult a Spiritual Directorto pray for their fellow members of Societyto use the sacrament of reconciliationto offer confidential pastoral care to fellow membersto attend all meetings of their group unless prevented by good reason.
Any one who reads this blog will know that all that is fine with me. The fact that the group takes its name from my liturgical hero Percy Dearmer is a complete bonus.