[Icare9]

Given that the Wellington had a max speed of about 230 mph, cruise (loaded) about 180 mph, and that Berlin is about 550 miles, it would have taken somewhere between 3 and 3 and a half hours to reach its target. Ouldeboom is about 330 miles from Berlin, or 220 miles from Feltwell. Depending on whether it was shot down before reaching Berlin, then it was about an hour or 80 minutes after take off, or about 5 hours if shot down on the return leg. If it crashed at about 1:30, then it's more likely to have been on the return leg, given the dark nights of November, so around 19:30 would be my guesstimate.
It's more likely that German defences would be more ready for returning aircraft, having been alerted by them flying overhead a few hours earlier. Also if it left about midnight it would be returning about 07:00 by which time it would be getting near dawn.
All pure speculation, but I hope it helps building a picture.