Ok so I've found some photos for reference. (Apologies for gratuitous 'dump')
There are posts/info on here and possibly YouTube on how to get off the SoS unit but my recollection is such: Apologies I'm not sure how far YOU will have to go to get to the 'other' end of your Antenna connection or if you'll have to remove or certainly loosen off the headlining, but you may well be able to pull the connection out into the open once you've dismantled/partly removed the Headlining Console. Again on here there are plenty of bits of info, but do post again if you get stuck or PM me direct.
With ignition off....
Use trim tools to get the front alarm section of Console out which is for courtesy lights etc, and unplug. Just prise it out but as always go steady.
Same again for SoS section.
Same again for rear AirBag section.
To make life easier I then pushed in (towards front of van), the 'Cubby Hole Blank or Blank for Leisure Heater Controls etc' next to the Head Lining at the rear. Some say it's moulded in and you cant unclip it, but it's not (well not on my T6.1) and I've put a photo below to show the clips so you have an idea. If you push from the outside and try and work from within the cowling to ease the clips off it will give.
There are then some torx screws to loosen the Cowl surround. But at this stage you may well just be able to get to your Antenna Bolt, and ease the connection to be accessible??
If not, slip loose the cowl, but from recollection, you have to ease out /disconnect the Alarm sensors before the cowl can be completely taken away. You'll need to plug the alarm bit back in again and leave it hanging, to lock the van without the alarm going off (I did).
If you go want to the drive around 'mid-job' and you are worried about Dash errors, simply plug the bits back in again but cable tie them out the way. Im pretty sure I didn't (just the alarm bit) but just to be safe I'd do it, as I'd hate to put you in a spot!
Antenna should just unbolt and lift off. (Some photo's show cable connection and bolt location)
Top tip that I did was, when removing the cowl surround, the rear clips (towards rear of van) are an absolute PITA!!!!!! (See phot 8 just before the sound deadening on roof) to get off without fear of snapping something. That's why I removed the cubby hole blank. Then from where the light/SoS bits go, I slid up a robust flat bladed screw driver and use this to help prise/release the clips rather than just pull on it for fear of snapping something. I slid it between the bottom of the metal clip, and the plastic tang and kind of twisted to help force the tang out (you'll get the gist I'm sure).
Please don't rely 'exactly' on my sequence as it's been a while, but if your considering attempting it you don't strike me as an idiot (no offence), so it will become apparent how it comes off. As I posted above, the first time I did it took me what seemed like ages going gingerly and feeling my way. Next day I took it off again as I wasn't happy with one bit of my wiring routes and I had it out in about 10 minutes with total confidence. Be slow but deliberate and search the guides on here.
Hopefully photos will help too.
Any more PM me
Edit to say you can just see where plastic (Let me break if you force me) Tang, goes into one of those VW metal trim clip/grips, hence use of screwdriver rather than just yank it off.
Edit to say now I've looked at this last photo again, you may??? have to remove or loosen off the front of the Head Lining to gain access to antenna connection. plenty of guides on here but do PM.
