Wellcome to the club. My SEN status is not recognised in many cases. So the good amenities like seat blocking/prefered seats are not working.
I always check if SEN is correctly printed on the boarding pass. If not I will hand it back. Some Check in agents say: "It does not matter." This makes me always upset.

I had it more than once, that I had connections and my incoming flight was late. The cabin attendand had lists of connecting pax, but had no clue of me.So no direct transfer. So I think LH-IT system is not liking me.
(maybe the same club that weero is in!)
I managed it most of the times but it was a hassle. I only missed one connection.

In one case I had to connect in BCN from LH to IB (the dark side).
The inbound flight was late about 1,5 hours. We arrived 10 minutes after the departure of my outgoung flight. The Cabin personal had no clue about this connection, but got informed that the outgoung flight was delayed as well. I had no problem and comfortably walked to my new gate.