The line i missed here was 23....Qb4!! threatening 24...Qd2+ 25 Kb1 Qxb2# if 24.Ng1 [uncovering a defence to the d2 square by the queen] then 24...Rxa3 and that us the reply to 24,Rd1 and 24,Ne4 and 24.Nc3!
The lasr move is the best defence which goes 23....Qb4!! 24.Nc3! Rxa3! 25.Nb1 Ra1 26.Ne4 Na3!!
It deserves to be in the encyclopedia of combinations, by informant, it is so complex and winning. And of course 24.axb4?? loses to 24...Ra1#