[interestednovice]

I suspect the "we're not able to detect..." might be a bit of deflection. It's perhaps more likely that they simply haven't got around to creating streams of the regional feeds yet...?

Exactly, that seems much more likely.

The whole thing about postcode during signup is/was primarily to enforce the ITV/STV split, but also a low-tech way of deterring signups from abroad working in combination with geo-blocking. They may well target adverts too, as adverts are not always part of the stream and often separate.

I imagine, with more people relying on these sorts of services as a full linear replacement, then ITV will have to follow the BBC and make full regional streams available.