Indexing nightmare

[confusedcyclist]

Thanks guys, I'll give it a go. Truly disheartening as I take great pride in fixing things for myself, but this is a battle I think I am losing!

Last chance to fix it myself and it's going to the LBS! Will report back.

 

[Globalti]

Just take it to the LBS and ask them to check the alignment of the derailleur hanger, which takes five minutes. If it's out, they will bend it straight but take the opportunity to buy a new one because they are sacrificial so they are made with a brittle, granular alloy that's designed to snap, protecting the frame. Bending will begin that process so it will snap at an inconvenient moment soon.