G.R. means Giudice Reggente. Fulvia De Luca is a so-called Giudice Ordinario (3rd level trial judge) attached to Section 9 - Family section - of the Milan Civil Courts where she transferred in 2015. After much thought, I think presiding judge is the best translation, even if "reggente" can also mean vice or deputy, as in awaiting confirmation of a full-title position. This is not the case with Ms. De Luca (see bollettino ufficiale with publication of the transfer). This is obviously a single bench, i.e. monocratic proceedings.