A resent post by Roger and comments thereon led to my realising there are misunderstandings on the intepretation of the polar field relationships.
Wilcox Observatory measure and publish a time series of the solar polar magnetic field, a difficult measurement. Started 31st May 1976, data point every 10 days.
Figure 1, straight plot of f10.7 radio noise as a proxy for solar activity and mean solar polar magnetic field.
Firstly here are some clarification notes.
The polar field is not the interplanetary field indirectly associated with terrestrial cosmic ray flux. This field at earth roughly follows the F10.7 / sunspot shape, is very noisy.
Neither is it the Livingstone & Penn finding about the change in sunspot magnetic field possibly reducing with time.