[AaronLancs]

Manchester tried something similar with their BBC radio station. That didn't work either, in any of their incarnations.  

(Source: Logopedia)

That's not really a fair comparison. GMR (Greater Manchester Radio) existed in the same era as GLR (Greater London Radio) and both are initialisms based on a logical name to describe the area they serve.

LDN was a stylised contraction of London and was an aimed at unifying different media channels under a single brand. It could have all been different as one plan was to name the newly created London TV regional news programme as 'London Live' which was already in use on radio and online.

I seem to remember seeing over on the Blue Place around 2005-2010 the Orange & Blue unused titles for "London Live" being uncovered or discovered in a "what could have been" thread.

If you want to see it search up the following
"BBC LONDON LIVE Opening Titles (2000-2002) CLEAN VERSION"
because if I post the link directly it will be removed by the mods as I think the YouTuber whose channel it is on is on the banned list and I don't want to have my post modified.

All I can say about the titles are thank goodness they weren't continued on with as they looked quite uninspired and somewhat (shrugs shoulders) meh as the smaller area of London didn't read well on screen, especially with the 'map' flying about.
But a more dynamic set of titles and an awesome theme tune came along with the branding to BBC LDN.