Thanks - I had a six letter word meaning BEAT. It turns out that BEAT is the rare meaning!
I have an ambiguity in th the letters omitted from 43 and 44, which is resolved, it seems, by the sixth word of the message. I would like the missing letter in 44 to be N, but my answer to that does not contain an N and it is somewhat vulgar. So everything fits nicely apart from this problem