I thought I should update on my progress. After about 8 months, I got a reply from Mr. Upton. I understand there was some kind of family matter, but that he is back to doing repairs now. I would still have appreciated some kind of reply to mail/phone calls during this time. However, in the end I think he handled it in a fair way: he apologized and gave a reasonable discount, and returned the camera quickly after this. In general I will say the quality of repair is very high: he did a full CLA of my non-working Exakta 6x6 (pre war) and two lenses, including changing the shutter curtains and testing/adjusting the shutter speeds. I believe the number of people who can service this camera is very small, but he is clearly one of them. While everything looks and works as it should, I should note I found a few tiny pinholes in the shutter curtain which can be seen in photos. Due to the difficulty of repairing my camera and replacing the shutter (which might be more beat up/bent than usual), I understand this was very difficult to avoid, and he has also offered to repair it free of charge (probably I can also fix it using some acrylic paint). To summarize: I would recommend Mr. Upton based on his repair skill, but make sure he has time to repair your camera, and try to agree on a fixed deadline beforehand.