Think it will fetch more than you think, depends if it's been recorded as an insurance loss (Cat C or D).
For me the Cat status is a moot point. It's done 150k, needs a bonnet and shows obvious signs of being very well worn. It appears to be a breaker.
The seller suggests you can drive the car home as long as it's booked into your local MOT garage. The law does not specifically exclude you from doing this - it only says drive the shortest distance to the garage you are booked in at. However if you were stopped and it came to court then reasonableness will be brought into it and I wouldn't expect to get away with having driven it 150 miles. Being up in Nottingham the alternative is £300 of transport for most of us in the south.
The photos also appear to be very carefully framed to exclude the areas where the seats could be worn. And at 150k you need to be realistic there.
The steering joint is £250-£300 from BMW with no alternative supplier producing the part from what I can see. I'd imagine it's not the quickest of jobs and might be one of those you wouldn't want to risk a second-hand part on.
It's already up to £400. For me it's got a couple of hundred quid left to go on it before it's no longer looking a deal. My 2.2 write-off with 97k miles was £1,000 landed and was a nice pre-accident car.