Thanks skyline, I also think that is the next step but I should mention I've just checked the voltage coming from the alternator and it isn't steady, it's jumping from 15v down to 7v, I'm assuming this is the voltage reg on the alt, I'm guessing because it isn't steady it's throwing the battery light on.. Maybe that's the first / cheaper option to replace the regulator.. It's funny that I'm getting a steady voltage at the battery end but unsteady from the alt to the ECM.

I measured it on the blue wire coming out of the alt and going to the ECM, I traced it up to the top of the engine, the wires join in a plastic box under the engine cover. I Was torn whether or not to replace the alt or the VR, I guess the safest option is to just replace the alt, I think I'm looking at $500 on eBay unless anyone knows of a cheaper option? I'll report back once it's fitted-now off to remove the alt, this should be fun!

I don't suppose someone wants to check their voltage coming from the blue wire on their alternator for me just to see if theirs fluctuates like mine? I want to make sure that's my problem before I purchase an alternator..

The car is now in with the BMW specialist, I should find out later today what the issue is, I asked them what they used and they said Pro logic or something like that.

OK, the garage has rang to tell me that it's the alternator - it has an intermittent fault hence the varying currents going back to the dash light, they wanted $2K for the new alternator fitted, i'll be buying one from a scrapper for $300 and fitting it myself shortly. Once that is fitted i'll have the ABS lights cleared and go from there... hopefully the new alt will fix the ABS lights, fingers crossed.

Basically because of the price.. Do I need a gasket for the alternator?

Update, I relaced the alternator today. Battery light and abs lights still on. Battery is charging fine at 14v. I'm peed off as the garage I took it to said "it took us a while to find it but your alternator has an intermittent fault" charged me $200 and that's that. I'll be going back to the garage on Monday for a refund as that obviously isnt the problem. I've read it could be the ignition switch? Or maybe even the cluster.. The ABS lights are still coming up with the same error "brief power interruption".