1 Having been sent on a business trip, he did not see Jane for three months.
2 Sent on a business trip, he did not see Jane for three months.
I can't put my finger on the difference. What is it?
1 Having been sent on a business trip, he did not see Jane for three months.
2 Sent on a business trip, he did not see Jane for three months.
I can't put my finger on the difference. What is it?
These complex past forms (have done, having done, to have done) are used when looking back at the event from some later point. However, English speakers often do not bother to use them when the temporal relationships are clear without.
So your no. 1 sets a temporal focus at some time after he was sent (not necessarily after he made the trip), where no. 2 does not set a temporal focus.
This difference has no effect when the sentence is taken in isolation, but someties it can affect the interpretation (specifically, the timing) of what follows, though I can't see how it might do that in this case.