Power Meters / Powermeters (SRM, Powertap, Quarq, Ergomo, Vector, Stages, power2max, P2M, 4iii, InPower, Cinch)

Thanks, but I may have already solved it, thanks to @Goyt . Unpaired the p2m from phone app and this evenings session had no drop outs. Need to do a few more before I can be sure obviously, but the last 5 sessions before tonights had drop outs, so am optimistic.