Then stop wasting money. Without a scanner you are setting money on fire.

Your best bet is to get ISTA working. I just diagnosed an identical fault on my other BMW. In my case, one of the ABS sensors had failed. The bad sensor appeared to be working but every now and then it'd send garbage data and cause the computer to think the car was in a full on skid causing ABS to activate etc.

I diagnosed it by asking a friend to drive the car while viewing the live data - one wheel suddenly looked to go from 30 to 0 then to 60 then to 0 then after a few seconds it was all good and in agreement with the other three wheels.

Not saying this is your issue, but seriously without a scanner I'm not sure why you'd pay to send stuff to BBA without actually verifying the fault!

Take it for a drive with your laptop running ISTA hooked up to it. Check that all 4 wheel speed sensors are in agreement. Then check the live data coming from other parts that influence ABS/DSC (steering angle sensor, vehicle angle sensor etc).