Coronation Street

That's not how most UK TV shows work. Granada didn't make it then sell it to the BBC, Granada will have been commissioned by the BBC to make it.

Granada may have funded some initial development work in order to pitch it to the BBC - but the actual show will have only been made because the BBC paid Granada to make it for them.

There are acquisitions - where a show is made for someone else, then bought by a broadcaster (this is how most US productions, and a lot of the BBC Four Nordic Noir stuff gets onto UK channels).

There are co-productions - where multiple broadcasters and production companies agree to co-fund the production of a show (this is different to buying it after it's been made)

There are commissions - where a broadcaster pays a production company to makes a show for them, and owns some of the rights to that show for a fixed period of time, before they revert to the production company. In the UK - when you see a 'XXYY production for the BBC/ITV/C4/C5' on the end board - that is almost certainly a commission from the BBC/ITV/C4/C5. (*)

In some cases co-productions can be commissions.

(*) Some BBC shows like Mastermind, Songs of Praise etc. are exceptions to this - as they are BBC formats that the BBC has tendered to third party producers. The independent production company will not retain any rights to the shows and are just paid as 'producers for hire' to make them, with the BBC retaining all rights.

In this case I'll bet you anything that it was pitched to ITV first before they turned it down and it was taken to the BBC for further development.

ITV taking money off the BBC to make a show about an ITV show. Seems like perfect sense to me.

I seem to remember Peter Ficham (then the ITV Director of Television) saying at the Edinburgh tv festival after it won the Bafta that ITV had turned it down originally and that he didn't regret it. As the topic was a bit insular and (paraphrasing) self indulgent for a mainstream channel.
The similar programme on the creation of Doctor Who didn't air on BBC ONE either.

Still aired on the BBC though, An Adventure in Space and Time was on BBC Two.

I think that’s happened a few times, The Deal was a drama about Blair and Brown that ITV was originally going to commission but they got cold feet as it was around the time of the Granada and Carlton merger so Channel 4 ended up commissioning it and it was a success for them.

Well, indeed - ITV Studios are just like any other production company, it just so happens that they also have a broadcaster as well.

And BBC Studios are now making programmes for elsewhere too.

the biggest TV event of the Corrie 50 celebrations was Corrie

The biggest TV event of Corrie 50 was Corrie. The biggest TV event of the Corrie 50 celebrations other than Corrie itself was The Road to Coronation Street.

I have to say I really loved 'The Road to Coronation Street' and ive re-watched it many times on DVD.

I do hope Corrie are able to do things to mark its 60th anniversary given the current pandemic, so far we have seen stamps released and there is news on a Corrie book being released later in the year. No doubt as we move towards 9th December there will be a lot more. I wouldn't be surprised if there is another box set with the 'best of' episodes but hopefully some different ones not released before. They might even release a network DVD for the 2010s as so far we have had every decade up to the 2000s. They might repeat episode 1 again on ITV on the night of the anniversary (which is a Wednesday this time) as they did for the 40th and 50th (or during the week if not on the night itself like for the 50th I believe it was on the Monday it got repeated)

Sad that so many of the Corrie legends are no longer with us for the 60th. In the last decade alone we have lost Bill Tarmey, Liz Dawn, Jean Alexander, Roy Barraclough and of course Anne Kirkbride.

Considering they've repeated episode 1 before it might be more interesting repeating more memorable episodes, and maybe if they're still a 3 a week in the autumn, which seems likely, they may do so in the run up to the 60th.

Also wonder if the 60th might become more of a standalone episode which they can get filmed and still air around the date even if other filming gets suspended.