Hi Outwest34au,
Yes, the lower Series II control arms
are different from left side to right as Tony C. has mentioned above.
Also note: I believe the Series I upper control arms are also so handed i.e front arm different to rear arm.
If your control arms (upper/lower) were sourced from different vehicles you could have a mixture of SI/II on the left side compared to you right side.
I have attached images of my front end which i removed from a '76 Series II XJ6. I also have scans of the Jaguar supplied Repair Manual that will give you the correct dimensions etc. Let me know and I can upload them
Regards Roy