Sorry about this very late update, but I'd been hoping to do so when resolved. Latest is:
After 3 attempts by H&L Motors in Twickenham, it was escalated to a Customer Relations Manager at VW Commercial Vehicles (i.e. at VW 'HQ') who commissioned specialist independent vehicle paint problem inspectors, PVWi who came down to see and assess the problem (Dec 2021). They concluded that earlier repair attempts had been more localised, i.e. just along the opening top-edge (probably due to insufficient funding authorisation) so they recommended a more comprehensive repair where the whole front-top 'pod' was painted from its front-edge (adjacent to windscreen) right back to underside the black rubber-strip/seal (so the paint masking-tape join-line would hidden). So H&L Motors did this again (while replacing that seal and applying 2 new corner clear protective tapes). For various reason it took 4-5 months for this to happen, but soon after this 4th attempt we were back to the same old problem: the tapes getting dislodged and the paint being rubbed and peeling-off. And, where the paint isn't being actually coming off, you can see ridges where there is pressure being applied (where I'd previously thought these were masking-tape edges). See attached photos.
While initially implying that H&L Motors had not followed the correct process, VW soon after confirmed that H&L had done even as requested. Everyone then agreed with me that there's no point in continuing to "put lipstick on a pig" until we get to the fundamental root of the reason as to what caused the problem in the first place - and what continues to do so. Need to understand that first (and hopefully rectify) before a 5th attempt at H&L. Because Martins in Basingstoke don't sell California's but only vans (which I didn't realise when I first went there) I was asked to take it to Lookers Van Centre in Guildford (where it was looked at by an 'expert California technician') - but he couldn't, at first glance, see anything obviously at fault structurally. Also, the build doesn't allow for any fine-tune dimensional adjustments (i.e. screw-holes are not slotted). Unfortunately VW Commercial Vehicles took this to conclude that they were now only providing "goodwill" to carry-on with investigations/repairs rather than it being undertaken under the original warranty, despite me raising it with VW Martins within that 3-year period and the first - but unsuccessful - repair attempt being confirmed as a legitimate warranty claim. While VW Commercial Vehicles say they will continue to help (for now?) this leaves me vulnerable to them pulling-the-plug on this goodwill if it gets too tiresome, complicated or expensive, or if they can't establish the reason for the problem (or if I continue to be a pain!). They say: "This is because the faults are not covered by warranty as no manufacturing defect can be found". Obviously I'm challenging this change in status, and countering that "no one at VW has established the reason (or even a theory at best) and that, until then, the only reasonable conclusion you can draw is that it must've been an inherent fault at the original build/assembly stage". But I assume for them to admit this - with no idea on how fix - leaves them open to me being allowed to reject the vehicle? Either way, Martins have confirmed they've alway believed it was a legitimate warranty claim (and I assume they're still involved in the admin).
In the meantime, Lookers have pulled-out of further involvement (best I don't say too much other than, I believe, a disagreement - or misunderstanding - between them and VW Commercial Vehicles). But the latest suggestion is that the vehicle is taken to another Van Centre (with a "California expert") such as SMG in Tonbridge (who I bought it from). This is being discussed now, despite it being a 3 hour round-trip for me. I keep suggesting that an 'expert' from VWs internal Technical Team comes down to see first-hand and help the dealerships, but I'm told this will never happen! I will try to keep you updated on a more regular basis as I still can't believe I'm in isolation here.
I suspect there are more of you out there with similar problems, but unless you open the roof, climb-up and look down on that front-edge you will not be aware. I only became aware of it when I saw one of the clear corner protective strips poking through the gap-line between the pop-up roof and top-front pod. But, for all I know, the paint could've been starting to rub-off 12-months earlier (and even as soon as I'd purchased it), but wouldn't have been noticed (because it looks relatively OK with the roof down). Please all have a check!