Shifting problems at both ends of the cassette

[Twilkes]

I bought a long cage derailleur to match the 32 cassette but also noticed a tiny bit of cable snag in the first bit of housing - could literally grip the cable and let go and the derailleur shifted where I expected it to. So recabled and used one of the ridged ferrules that came with the shifter in case that made a difference.

So correct cabling, derailleur and chain length and all working fine, and a spare derailleur for a future fixup bike if needed.