seem to be mounted on one plate.

So looking at that

Are these fuses replaceable individually or does the set of 4 come as one unit only?

do you see a way to replace just one?

one of the 60A fuses was connected to the caravan power and popped even though there was a 50A secondary fuse next to it.

Sounds like the 50A came from Amazon

Spoiler: Amazon Fuses

 

Posting your year would GREATLY help.

One piece, 7P0-937-629-A dumb, as they're otherwise standard MIDI fuses.

 

My experience of owing a Touareg so far has been to discover an entirely new fusebox I didn't realize it had once per year

 

Hi Rag,
I would be pulling it apart and drilling out the rivet and replacing it with a nut and bolt. No functional loss with less impact on the bank account.

Stu...

 

On my 2004, these fuses are bolted on both sides. I keep spares for these, in case I blow one with my accessories. I have never seen the fuses with rivets. Dealt with these while installing the 2nd Battery.