So probably the final update...
The logger work has been done and seems fine - just need to test with a full logger.
Today has been errors day, brought the hardware indoors, threw out three spiders, disconnected the anemometer, made sure the right things went invalid. Disconnected the rain bucket - nothing reported from the hardware at all, it just carries on with the existing output. Would have been nice to make the relevant channels invalid, but can't do anything about it.
Did spot one bug, I was calculating relative pressure from the outside temperature - nice one to find. Next, bung the hygro/thermo sensor in the freezer to make sure I have my signs right - all fine. I can report it works fine at -22?C (which was a surprise! I've seen more expensive sensors die on that test).
Final testing is remove the batteries from the hygro/thermo sensor and make sure we behave appropriately and if that's fine, job done.
In conclusion:
This is a tricky unit to interface to - I can see many 'gotchas' that could happen. Total time has been approximately 40 hours development, that broke down as pretty much 20 to get it going then another 20 to interface to the logger and fix bugs.
If it proves stable over the next few days, it should make an appearance in the next 1.1 development release.