For completeness, by the end the list of issues I had experienced included:
• Water ingress through the overhead roof console
• Standing water inside the pop-top roof area
• Interior lights switching on and off by themselves
• Emergency/SOS calls triggering while driving
• Starter battery losing around 5–10% per day while parked
• Condensation in a rear light cluster from delivery
• Excessive rattling, squeaking and banging from the rear cupboards
• Travel Assist warning sounds that were almost inaudible
• Crackling/interference affecting Android Auto and the VW voice assistant
• Carpet mats paid for with the van but never supplied
The water ingress and electrical issues around the roof console were obviously the biggest concern.
The van went into VW several times, including spending a full week with them initially without any of the faults being resolved. I eventually gave them a final opportunity to repair it and it then remained with them continuously from just before Christmas until February.
During that period major parts were replaced, including the roof control unit and aerial assembly, but unfortunately their own post-repair testing confirmed that water was still getting in.
At that point the van had spent a significant amount of time off the road, the repair attempt had failed and I’d completely lost confidence in it, particularly around the potential longer-term effects of water getting into the roof electronics.
I therefore exercised my final right to reject it under the Consumer Rights Act 2015 and the rejection was ultimately completed.
Although they did return the vehicle with the replaced roof panel, which as I said appeared to have fix the water ingress I had already rejected it by that point.
The particularly frustrating bit was that despite owning it for nearly 6 months, we had never actually slept in it or properly used it for camping. All of this happened before we'd really had the chance to use the California for what we bought it for.
A real shame as I genuinely wanted the van rather than my money back, but eventually there were just too many issues and too much uncertainty to take it back again.