rust in Mk6 seams

[Chrispook]

Hi, I'm looking at bidding on this beautifully preserved LWB Mk6.
https://www.turners.co.nz/Cars/Used-Car ... t/16413311

Its been a police van and its been maintained perfectly. The engine looks like a show piece and there's just 80,000km on the clock. My only concern is some rust in the seams and around the roof gutter. You can see some pics here: https://goo.gl/photos/2RxuduhuzcmtiYLHA

Pics 1&2 are the driver's side. Pics 3&4 are above the driver's door or above it. Pic 5 is above the passenger door.

I can see that a couple of these spots have been tidied up previously. Now it looks like the rust has eaten back through. My question is: can I fix this? I'm worried that even if I strip out the rust & seam sealant with a wire wheel I will still leave some in there to fester and return. I'm not keen on having to constantly battle rust for the next few years!

Thanks in advance for any advice.
Chris