Hi Paul
Just looked at that before your new message. Yes, it lists Whitecross Street as missing but seemingly that bit which is in the parish of St Luke's (piece 668). The Whitecross St prison (according to the NA page) is in piece 727 but this does not appear on FindMyPast's list of missing 1841 pieces! Or is it simply missing off of the missing list...ha ha.
Will chase this up at some future point at the National Archives.
regards, Paul