No one wants a base level petrol BMW, they are very hard to sell, most second hand buyers are looking for diesel nav, heated seats xenons etc. Most people buying at this price are not prepared to pay BMW maintainace or put up with 30mpg.
As an example of what is likley to go wrong, Auto box sumps often leak, not terminal but £450 to fix at an indie. Now your manual focus TDI might seem a bit more attractive.
Anyway, I’m sure it will be a good car, but its a very niche market so will be hard to sell and even from that price depreciation will be hard. You would keep more in an equivalent priced Octavia IMHO!