Thanks, Staffordjas.
I now leave Edgbaston every Thursday at 10:00pm, heading for Stafford. Coming home via M5/J2 is always an option, though recently I've been going through the centre of Brum, then the Aston Expressway to the M6, and it's been fine. However there was one occasion when spaghetti junction was closed and I found myself on unfamiliar roads trying to find my way to J7, the Great Barr junction. I was just wondering if closing M5/J2 was a regular thing, every night. Checking AA Roadwatch may be the answer.