Plenty of zeds are well looked after and dont come out in winter so dont worry about the mileage. As you will find out, there are lots of members who really look after the cars so one in good condition is also not surprising.
As for the Subaru dealer not knowing much about the car, get used to that, many Nissan dealers are about the same.
"Thanks and look forward to fully joining the club soon!"
You are in bud, its as painless as that.