Well, the plot thickens....It appears that the earlier (than mine) chassis used the mythical £6 dipstick (8Z0115611G).
It requires a different funnel AND the ball on the dipstick is in a different place to the revised version (as fitted to minewhich is £24 and fibreglass (8Z0115611R)).
Crucially, both 8Z0115611G and 8Z0115611R are the same length, but the moulded balls are in different places.
As an experiment.....
I've ordered a metal dipstick and early funnel.
My plan is to remove my funnel, fit the early one and cut the ball off the metal dipstick and use the early setup.
I have to cut the ball off because it wont go all the way down the diptube, as the early one use a different diptube (£164!!!).