Definitely not Openreaches.
Yep, can also confirm not openreach or any of the previous companies
So last night, i managed to shine a light down into, get a good look down the hole thats appeared in this cover. I was able to see what looked like a passage for water and openings at either end of it.
So i've reported it back to Severn Trent again, as it's got to be theres I suspect now so hopefully they can fix.
OR did have a quick look this morning too and said it's definately not theres either.
Looking at the logo, the bar to lift and your dimensions, it might be one of these:
FWIW, I would have thought that this cover, although covering ‘water’ services, because it’s on the OP’s property is nothing to do with Severn Water in that , when they visited previously, and said something along the lines as, ‘nothing to do with us’ , wasn’t to say the cover wasn’t an access point to water/sewage, just that it’s the householders drain cover , and the householders responsibility to replace it ( if it needs to be replaced )
That would be the most likely answer, and the image on the website posted by @darrendz1 , is the nearest match.
Severn trent turned up again today and now agreed that it is there responsibility due to it being a shared drain.
Only issue now though is that they couldn't actually remove the cover so likely to need to dig.
Anyway, thats for everyone's input on this so far.