Update...
After opening up a new Openreach case and then chasing, chasing, chasing after weeks of no reply
Finally got a reply on Sunday:
"plant protection manager has tried to investigate this matter with no avail..."
They went on to say they are unable to proceed without a post code etc. !!!???
So I pointed out to them I had provided full postal address, post code, longitude/latitude of fallen tree, photo, line drawing showing tree location so there's not much more I can do to help.
Got a phone call from a BT surveyor this morning - at the end of my lane looking for the tree

Told him I'd be there in 5 minutes. Thoroughly Nice chap. Saw the tree and immediately agreed they will do something about it before it brings the line down!
Was apologetic over how OR had handled my report when I explained things to him...
Hopefully the tree will be removed in the next couple of weeks
It might just me, but why do you have to FIGHT for everything these days!

Pull your socks up Great Britain...