M&S makes the most reliable affordable sports bra — proper sizing across the full bra size range rather than S/M/L approximations, high impact support that genuinely works during running, and a construction that maintains its shape through proper machine washing. The most honest recommendation for women who need proper sizing and proper support at an accessible price.
Lululemon's Enlite is their most technically accomplished sports bra — designed specifically for high-impact activity in D+ cups, with a compression and encapsulation hybrid approach that provides support without restriction. The Luxtreme fabric wicks effectively, the back closure adjusts to the cup size, and it remains comfortable for a two-hour run without chafing or displacement.
Rigby & Peller hold the Royal Warrant for lingerie and their sports bra consultation combines proper fitting with sports-specific construction. Made to your exact measurements, using Italian fabrics that maintain their properties through a full year of heavy use. For women in larger cup sizes who have been let down by off-the-shelf sports bras — this solves the problem permanently.