It arrived this morning, so I got on and fitted it (whilst I should be working!)
It was very straightforward to fit, I removed the old inner cable (as it would have been too short) and cut down the outer loop.
Once fitted it, took about 15 minutes of fine adjustment using the barrel adjuster on the mech to get it indexing up and down the cassette properly, but it does work, the drivetrain noise is quieter because the chain is now in the right place and the indexing is so much smoother. So really pleased, for £35 a really nice easy well engineered solution. So that's it, all finished. On to the next one