Mundano of 2010 would be by choice. I’ve the 1.8TDCI (truly the dullest car in the world, much pokey-er models are available)
Picked mine up in immaculate condition, FSH, timing belt done, 95k miles for under £3k and that was 2 years ago. It’s needed an only an engine mount and tyres in that time (and 23k miles)
It’s economical, comfy, relatively cheap to fix . Also, the ones pre 2011 I believe don’t have DPF (mine doesn’t anyway), this something to consider as £££ to replace from what I’ve read.
My previous car (before I became a student again) was a 2012 BMW 320D. Whilst the mundan-o is obviously completely different to drive, it’s not caused me to sob quietly into my corn flakes as much as I thought it would.