Ref discussion at CA. There are various adjustments in HadCRUT and other
global temperature series, and I removed those adjustments to obtain more accurate reconstruction (original obtained from
Juckes et al supplementary):

The original series is here, and this improved temperature series is here.
Looks quite different, but no worries. Just imagine that the new one is the correct. Then take Juckes et al JBB standardized proxies, and
check the correlations. They seem identical, 0.2810970282611 - 0.2810970282611 and so on. You'll get the same JBB INVR reconsruction
using these temperatures.