Uncle-Badger

New to forum so please excuse my ignorance: I have a late model e39 525i M-Sport Touring which has been very well maintained and serviced, just ticked round to 100k miles. I've had it three years but am starting to get worried about it’s electrics: in December the car died on me and it was diagnosed as a bad battery and fried Alternator. Ive just driven down to Cornwall from London, great trip, car faultless or so it would seem. However the dashboard lights started to come on on day 2, EMS, ABS, BRAKES, DSC, Airbag. Lit up like a Christmas tree. It laboured to start slightly, then the following morning was dead to the world. The AA came out and diagnosed a faulty alternator AGAIN. I had noticed a bit of a low whining noise in the days leading up to this. So from what research I’ve done I’m thinking it was bad bearings in the new(ish) alternator. I’m a bit alarmed that it could do the same thing again so soon. Could it be a fault in the car that’s causing this or is it just a dodgy recon part? It was supposed to be a new one when it was fitted 6 months ago but the AA chap reckoned it was most likely reconditioned. Id be keen to know what people think. Also: I previously had the issue with the Hedgehog resistor/heatsink packing up so have previously replaced that with a brand new one from GSF. any thoughts or tips would be great, is it time to ditch the banger? Which up until now I was quite proud of...