V70 Brakes: ABS system or reluctor rings

[D5V70]

I see that I am not the only one suffering some recent brake problems and the other threads have given me some great knowledge

I recently changed my wishbone bushes and noticed that my NS driveshaft outer CV bolt had infact almost come out completely . I tightened it up and the car went for an MOT and all was well .
Not too long after I started getting the ABS warning and cutting of power on slower left hand tight bends .
This has now rapidly progressed to the ABS system not starting at all and once I hit the magic speed ( which must be about 30 mph ) the system just disables and I forget all about it
I had a good look and yes the NS front reluctor ring would seem to have a small split in it and it is a bit uneven . The sensor is perfectly lined up and I had it out and eyeballed where it sat etc .

My question is whether this small split in the reluctor ring would actually cause so much problem at very slow ( walking even ) speeds ?. Is the system really that accurate ?. Ok , if I had a few missing teeth then I could maybe see it , but is a small crack going to make this much difference . I really can't see it and hence I am wondering whether to try buying a new sensor instead .

Any help appreciated , thanks , Gordon