It is likely that more than one English hybrid or cultivar was called ‘Victoria’ or similar.  For example Rhododendron ‘Victoria Reginae’ was exhibited at the Massachusetts Horticultural Society on April 19th, 1889.  [Wilson & Rehder p.99].  The authors suggest that this hybrid belongs to a group of hybrids raised by William Smith of Norbiton in 1842 between a hardy Rhododendron seedling and Azalea [Rhododendron] sinensis Sweet, called at the time Rhododendron Smithii or Rhododendron x Smithii, or alternatively that the parentage is ‘a yellow form of the Chinese Azalea and Rhododendron caucasicum, the latter of which it resembles in habit.’  [Robinson, Fl. and Sylva II, 152/1904,  quoted in Wilson & Rehder loc cit].  If this association is correct then ‘Victoria Reginae’ could be synonymous with Macarthur’s ‘Victoria’.  I have found no specific description of ‘Victoria’.  Rhododendron x Smithii aureum is figured in Paxton’s Magazine of Botany [MB p.79/1842].