Just a thought, but what diameter are the rear discs? It's just possible that some of the parts are the same as the front setup on one of the 'cooking' models.
Personally I wouldn't sweat over the wear indicators; if you can find a dimensionally identical set that's lacking this 'feature', they'll still work fine. Most of the time, some other part of the brake system usually fails before the pad with the sensor in it, and regular maintenance will easily pick up a worn pad if done properly.
I wouldn't sweat over the compatibility checker either. Whenever ECP has a choice of parts, half the time the compatibility checker gives you the wrong ones anyway.
I like the coated discs we got as it keeps the discs looking shiny new on the inner and outer areas that usually all rust up. Obviously the pads wear the coating off where they ccontact but as that shines up everytime the car is used looking through the wheels everything always looks like new.
The Pagid discs from Euro have a similar coating. Much easier than having to degrease off the usual muck some of them come packed with.
Cars only done 15k, didn't expect to have to change manufacturer fitted discs just yet.
Depends so much on use; I've seen 60k+ from pads on a carefully driven road car, and also seen a newly fitted set worn out after a single trackday.
Hint: dedicated ecodrivers generally don't buy 165BHP small hatchbacks. With modern friction materials, time is a factor also; there's a high iron content in the pads (and obviously the discs), so corrosion plays a part too - though you rarely notice this, as the pads & discs are swept clean each time you drive the car.