Aperiodic element distributions can reduce reflectarray cost and weight by 35%, but they introduce two problems absent in periodic designs: (i) the required phases uniformly span the full 360◦, demanding wider S-curve coverage than a single-parameter element typically provides, and (ii) non-uniform inter-element spacing causes physical overlaps when variable-size patches are used. This paper addresses both problems through a proportionally notch-loaded rectangular patch element at 28 GHz. The element has a fixed width Wp = 2.5 mm, variable length Lp, and two symmetric notches of depth d n = 0.15Lp on the non-radiating edges, yielding 336◦ of phase range with 211◦ of independent fine tuning on 0.508 mm Rogers RO4003C substrate. Combined with a stealthy hyperuniform distribution on a 120 mm diameter circular aperture, the design achieves 19.7 dBi realised gain at 27 GHz with 287 elements, 0.2 dB above a 441-element periodic reference, while using 35% fewer elements and exhibiting 0.3 dB lower sidelobes. To the authors' knowledge, this is the first reflectarray to combine a proportional notch-loaded element with a hyperuniform distribution at millimetre-wave frequencies.