I've looked at my current, nearly 10-year old pair, and it's made in China too.
You have to specifically buy from the Made in England range to get boots that aren't made in China or Vietnam.
I have read concerns about their declining quality as well, so not trying to invalidate your point, but I think the problem is Helen and not the quality of the leather.
Remember that she ruined her first Stella McCartney shoes, more recently she discovered she'd stored her coats improperly and had burned a hole into one of her faux fur coats (which could have been a serious fire hazard for her house!). Also not bothered about keeping her very expensive sofa clean or in good shape. Drilled a hole into the kitchen wall without checking for electric wires.
Remember she's also careless with living things: she's let fragile exotic plants rot in her garden, she drives recklessly with little regard for other road users, she prefers to "let her dogs be dogs" (run up and down the stairs/the sofa/bed) even if they risk injuring their little legs, she didn't care properly for the fish in the massive tank they had in Maff's flat and they all died, etc, etc, etc...