I measured Saturday's route on Anquet (1:50,000) at 22.6 with 1023 metres of ascent.Don't know how accurate that is compared to your Garvin (sic) Graham.
My Garmin was 3634 ft ascent and 3613 descent
I gather Garmins are not very accurate on ascent/descent although there is not much tree cover on the Rombalds to upset them.