Noticed this by chance on the current project golf - it was only visible with the boot halfway ish open. After checking a couple of other mk2s this seems to be fairly common - mine was easy to deal with before it got bad, but could be a bigger job to fix if it rots through. Anybody else noticed / got this issue?
Yep seen it on a few of mine in the past along with the opposing face of the tailgate on one and also where the wiring boots are fitted as well.