David — I am surprised that you think that I would post information of this quality here without checking it first. Of course I did a thorough check on Google before posting.
That revealed the museum website that you found, containing information up to the 1960s merger/takeover. Several other sites continued the history. Of particular importance was
this page from
http://www.purelysilver.info which adds:
Although the name is still used in retail outlets, Walker & Hall were taken over ... in the 1960's.
So, irrespective of where it was made and what name was on the factory, it looks as if the range was still being sold to the public as a Walker & Hall product made of Sheffield Steel when that web page was written, presumably after the 1970s; either that or it had been discontinued by then, but had always been sold as a Walker & Hall product.
Whatever, I didn't perceive it as necessary to clutter my post with unnecessary and complicated speculation about the history of the Walker & Hall factory and trading name.
Bernard C.
... and the Australian Male Voice Choir was magnificent today, despite having a Wimbledon official as a minder, a security guard, and, at one astonishing point, a stiff talking to by head? of security, who presumably threatened to do a meat-hook job on them behind the bike sheds, possibly with the SAS using them as target practice!