This regex gets me the "last" STGN number before every IRV-occurrence,
which I think is what you're asking for.
I don't understand how this relates to the names you wanna find but
maybe this'll help you under way.
[0-9A-F] finds hexadecimal numbers, which I think you're
working with here
- Basically this regex is saying "give me the STGN number followed by
anything that isn't STGN and then IRV"