Gentlemen,
Jumping on this thread of several months ago, the capillary tube routing in front of the firewall is very clear but the only thing I have seen beyond there is the factory manual diagram showing a sharp turn and circling around the imaginary heater. Pigott in his book also has a photo showing the sharp turn at the corner of the battery box, albeit one without an O/D relay. There is probably enough space for it above the relay.
Does someone have pictures of an original routing from inside the firewall, around the box, and around the heater to the gauge; showing where the (brass?) clips are attached?
Regards, Walter