There's very little speculation on what I said before -although there is some.
I have seen most of the 60s mss and I have read most of the (unpublished) correspondence from the period. There are quite a few patterns as regards submitting and publishing. Some mags were extremely fast to publish whatever B. sent to them, and others were slower -and I think I have a pretty good idea of which are which.
B. wrote less poetry -and submitted to less mags- in 1962, reaching a (bottom) peak in 1963. There's a clear upward pattern in 1964-65, no matter what B. said about slumps or blackouts. In 1964-65 he was in quite a few mimeos; the mimeo editors were clumsy and most mags were awfully produced, but they were fucking fast, and B. loved that. I'd say that 90-95% of the stuff published in 1964-65 was written in 1964 or early 1965, not earlier. In fact, he wrote so much in 1964 that editors such as Bryan kept his poems for several years, only to finally reject them. A large number of the poems in At Terror Street date back to 1964. And, oh, yes, all poems in Crucifix (1965) were new poems, while the ones in It Catches (1963) were old. Again, those are facts. A most productive blackout, sir.
In the case of At Terror Street, you're right, mjp, there was a lag between writing and publication. But that was not the case in 1962-63. His (poetry) production decreased in 1962-63, and 1963 was the worst year of the decade in terms of periodical appearances. So the dip in 1963 (mostly based on his 1962 and early 1963 output) followed Jane's death.
We could argue for centuries non-stop as to wheter Jane's death had actually anything to do with the dip in 1963, or if it was a true consequence of B's "depression" or not. Who knows? All I'm saying is that the dip took place right after Jane's death, and that is the main reason I can think of to explain the decrease in publications.