The BBC Children in Need appeal held in 1992 was marked by a rare HMSO-wide competition. Unfortunately(?) the answers page is missing, but you may wish to take a guess. We are fairly sure that we know ten or eleven of them, but not all.
Some are more difficult than others – J, L and M for instance.
No prizes, as HMSOldies is currently negotiating to take over Twitter from that Mr Musk and we need the fifty quid.