Following epic session finally have WeeWx up and running. Learned much & happy with this software.
Vanilla RaspberryPi -> Vantage Pro2 -> Clean install WeeWx, Zero customisation.
Have repeated above about three time too get here so have learned a bit about the overall process.
I have one tiny issue and I wonder if anyone has seen similar and could offer pointer.
Attached image is of wind graphs from current running setup.

"Something" does not look right to me! This being a vanilla install I thought I would ask before I get into ANY "investigation".
Hope above makes sense.
Thanks for any suggestions.
Regards.
Frank C.