So far, from the front of the green bibles, I have accumulated these below. All measured at rest (centre of the sliding joint) and I'm not convinced the mm/inches conversion is correct - but it's copied straight from the book! Might explain LR's engineering "tolerances"
Series 1:
86, 88, 107, 109 Front: 654mm / 23.812"
86 & 88 Rear: 554mm / 21.812"
107 & 109 Rear: 1087mm / 42.812"
Series 3:
4cyl Front - 604.8 mm / 23.812"
6cyl Front - 693.7 mm / 27.312"
88" Rear - 554.0 mm / 21.812"
109" 4cyl Rear - 1042.9 mm / 41.062"
109" 6cyl Rear - 955.7 mm / 37.625"
Any measurement is good - but if anyone has the green bible for other models you might find it written in there in the tech data section?

