Wholly unrelated -- we don't even trace our apostolic succession via the same route. (On the off chance you're interested: the founders of the UGC were consecrated by Bishop Robert Monroe of the Liberal Catholic Church, and John Gilbert and several other UGC bishops were later consecrated sub conditione by Bishop Herman Spruit of the Church of Antioch. The Thelemite churches, as far as I know, get theirs by way of Crowley, who got it from Theodor Reuss, who got it from Gerard Encausse aka Papus, who got it from Jules Doinel and Jean Bricaud.) While the UGC does not reject the so-called "Law of Thelema" -- if a member wants to follow that, they have the right to do so -- it does not affirm it either, and by and large the UGC bishops I knew were not fans of Crowley. (At all.)