1.24m incl +1 according to Bothersbar (maybe slightly higher because they do it for the entire slot rather than tapechecked).
Anyway, BBspy is the one to look out for with officials as they have +1 in most whereas other sources don't (I emailed them the +1 ratings as a poster from DS who is reliable gave them to me), so I am working with BBspy quite closely regarding ratings:
http://www.bbspy.co.uk/bb15/ratings/official
Current series average if 1.58m. Hope it doesn't drop under 1.55m, if it stays above that it will be rounded up to 1.6m and therefore average the same as BB12 and BB13; so would be nothing to worry about.