So 33 encoders plus shipping & VAT to the UK from Digikey in the US cost about $70. I'm going to make a video of what involved for any one else who has the same wonky encoder issues and is looking to replace them seeing as Arturia are more interested in all the new toys they are temping us with than fixing the older stuff.
It would be great to have a video. Indeed the price tag of the bourne encoders isn't the issue. The technical documentation has some photo's how to disassemble and reassemble an origin keys for replacing the screen and hermitnerd also had some pointers from his repair. This made me hesitate as I have done quite some soldering, but must admit I do not have a good record on hardware repairs
Philippe mentioned some "special tool" is needed and i wonder if he meant the tx 10 key which I already found at my local hardware store.
If I feel confident enough I would certainly opt for replacing the encoders to assure longevity.