Don't forget many aircrew officers will also be caught out by the loss of 'Family Allowance'. A recent member of my team - Flt Lt PAS at top end of the pay scale, with 3 kids under 16 lost iro £2k per year.
That loss, to a lesser or greater extent, can be mitigated
if it was appropriate for him to contribute to a personal pension. Gross annual contributions (after his/her 40% tax relief uplift) are deducted from his/her salary which is then used as the reduced benchmark to establish eligibility for child benefit. Eg; salary of £60,000 results in complete loss of child benefit but gross annual pension contributions by that person of £5000 reduce net adjusted salary (for purposes of child benefit eligibility) to £55,000.