It's nice to see one of these huge saloons being restored as there are so few around now. They were never very popular even when new, but paved the way for the XJ6 along with the 420 which was the last iteration of the Mark 2 basic shell.
Congratulations on the fantastic job you are doing on restoring your car! Where on earth do you find all the parts? At the moment I am doing some repairs on my 420G as well. In The Netherlands too. Perhaps we can get in touch and exchange some parts and information. Looking forward to your reply.