Did you try the second hand piano stores, they could be interested in it for free as moving these things imply some knowledge as they need to be disassembled?
Mildje!: My project almost 20 years ago with 3 basses and 1 drummer and a single track of 45 minutes named Stuyvenbergh (which means mountain of dust in ancient Dutch) and subtitled Arhythmic Deconstruction... It says enough.
6 months of rehearsal for a unique concert that was sold out...
Fodera, Sire, Warwick, MTD, Ibanez, Ken Smith, Status (the Hellborg model was even running on 4 batteries, so 36 Volts...), loads of luthiers basses, ... have an 18 Volts preamp installed.
I bought a sixer headless bridge system from André and the quality is really top notch.
Beware that there are bad imitations available on the internet.
You can watch them on his Reverb store: https://reverb.com/shop/andres-gear-outlet-227
Or on his eBay store: https://www.ebay.com/usr/apassini98
Or check his website: https://novaguitarparts.com.br/portfolios/ponte-headless-para-baixo-4-5-e-6-cordas/
If you want to be a bit reassured about delays, I waited my Leduc U-Contrebasse 6 EUB (called Moaï ) for 7 years and my Leduc U-Basse 6 fretless is going to delivered in a few weeks after more than 5 years of waiting.
But Christophe is a friend and you know how it works with delays and friends...
That said I always had news about the building progress ... when there was some.
These are excellent lightweight replacement bridges, not sure they will fit a Bongo... Just ask them.
https://www.ampshopbassexchange.com/product/albridge-parts-mq5-sterling-music-man-replacement-5-string-bass-bridge-black-18mm-string-space/
https://en.m.wikipedia.org/wiki/Left-_and_right-hand_traffic
If you read it, you'll notice that right hand traffic is the most common worldwide by a huge margin.
You'll also notice that in ancient times people were driving in the middle of the road and when crossing, they kept the ... right side of the road, so please stop with this absurd assertions.
And once again U.K. was, is and will always be in Europe, but decided to get out of the EEC, which is something different.
Just for the record @Chienmortbb:
https://mossmotors.com/how-to-positive-or-negative-ground
And what I wrote were just facts as I don't care what you use as long as you don't pretend they are the only correct options.
These were just to demonstrate that there's no right option, so a truss rod is not working in reverse, but is a left or right thread working system and both are totally correct.
Got it?