As far as i know, it's a dealer only part. You might find one on
https://www.gcp.se/en/
which is the Volvo Genuine Classic Parts site. Navigation is a bit sketchy but with a bit of perseverance you should find the one you need. Wasn't sure which version of the B230 you had and it showed different options for a lot of things so i couldn't find a definite part number.
The other thing is, does the drain tube direct the oil into a particular area of the sump for any particular reason? I'm wondering if the drain tube is strictly necessary, i've never looked into the reasons it has one. You might also be able to make one from microbore copper pipe as an alternative as well.
