Thanks for the advice, and particularly the link to the people who have been working to work with the acu-rite data on an arduino. I missed that in earlier searches, though it looks like it may be for an older device that, for whatever reason, isn’t compatible with the sensors and receivers I’m using. Still, it is probably a good starting point.
This might be a more ambitious first-project than I anticipated, but I’ll probably pop for an RX and an arduino and see what I can get with a weekends work. If necessary, I should be able to use DNS hijacking to get at [the data the acu-link bridge is pushing up to the web service when it comes time to interpret the sensor values from the decoded bitstream.
For what it is worth, over on Jeelabs I found that the RM12B has an undocumented mode that allows reception of this type of signal too.](AcuRite Acu-Link Internet Bridge (09150TRX): Accessing Local Data « Modern Toil)