I've done the Betcam/Betamax thing before I believe. Sometimes I never learn.
I presume then somebody at ITV could have digitised the 1" tapes of Hardwicke (or at least copied them to something more modern, D2 or something?), as looking at pictures of the 1" tapes they look like hulking great things that take up a shed load of room.
Ha ha! You should see 2" tapes...
But yes - the original masters may well have been transferred to a new format.
I don't know about ITV but the BBC did the following (approx) :
2" open reel dubbed to D3 Digital Composite cassette (D3 is a 1/2" composite format, D2 was a 3/4" composite format)
1" open reel dubbed to D3 Digital Composite initially - but then...
1" and D3 dubbed to DigiBeta (a 1/2" component format) (via Transform PAL decoders that are reversible) and uncompressed LTO data tape
The LTO data tape is now being ingested as IMX50 MPEG2 into the BBC Digital Archive.
So for 2" and some 1" there will be a D3 (now increasingly difficult to play), and in many cases also a DigiBeta (still easy to play) and an LTO data tape, which can be automatically migrated to new data standards, and in some cases also an online IMX50 copy in the Digital Archive.