Va bene, lo farò subito. Intanto, mi puoi confermare la mia traduzzione (in inglese)? Da madrelingua inglese, credo di averne capito il senso, ma non ne sono sicuro...ci sono forse sfumatture etc.
I think we are going about this the wrong way.
"Manco a farlo apposta/neanche a farlo a posta" is not a very uncommon expression, but not very common either, and it does not have one fixed meaning only. Being, manco a farlo apposta (what a surprise!), highly contextual, I think we are a lot better off looking at a number of examples where this expression is used, understanding the exact meaning and then figuring out how to convey the same meaning in English. Let's try :
1) È uno scandalo, purtroppo, destinato a non allargarsi.
Quello che ha visto protagonista, manco a farlo apposta, la Calabria. (blog 'Lo statale jonico') : Here it means 'no wonder, unsurprisingly'. (Calabria is said to be rife with corruption)
2) Ed è ancora singolare che simili proposte siano giunte, manco a farlo apposta, dal gruppo Verde/Alleanza libera europea. (europarl) = Here it means 'what a coincidence! = and it's no coincidence at all' (Here it sounds like the writer has some beef with the Greens)
3) Avevo appena finito di lavare la macchina e, manco a farlo apposta, si e' messo a piovere. : "... and, as if on cue,..." (It happened just at the wrong time, as if on purpose to antagonize me)
4) Ero al ristorante con Giuseppina per il nostro primo appuntamento e, manco a farlo apposta, arriva il suo ex con un'altra ragazza. : "..as if staged.."
Basically, the main idea in this expression is that something (often just slightly) negative happened just at the right time, or in the right circumstances, as to annoyingly affect those involved.
It often does not really add much to the sentence, look at these two examples :
Mi ha portato un dolce, e sono in dieta.
vs
5) Mi ha portato un dolce, manco a farlo apposta sono in dieta.
Regarding your 'as it happens', my feeling is that it could work for (5), a lot less well for the other examples.
I hope I haven't added too much confusion to an otherwise simple matter 🙂