Limb scored either side of half-time to seal the deal for Martyn Bunce's side, with United hitting back in the 56th minute with a header from a trialist.
United youngsters Owen Sheriff, Finlay Armond, Han Stevens and Zane Millar were joined in the squad by an influx of trialists.
Boston United (3-4-1-2): Trialist A; Trialist B, Owen Sheriff, Trialist C; Trialist D, Trialist E, Trialist F, Trialist G; Trialist H; Trialist I, Trialist J. Subs (used): Han Stevens, Zane Millar, Trialists K to T.
Referee: Alistair Wilson.
Attendance: 650.
PIC: Oliver Atkin.