If you want a small, great performing, brilliant handling, and fast estate, then BMW have got it absolutely licked with the current 3 series (or any of the last 2 models tbh).
However, if you want more room (and really, that’s any significant space, as the 3er touring is small inside) then you’re either going to have to move up to a 5er (same range of excellent engines, and pretty similar good handling) or branch out into an Skoda, A6, C class, Mondy or similar.
£10k is actually a slightly difficult amount of money to spend, because in that region sit well spec’d but higher mileage older model cars AND lower spec’d but a lot newer/lower mileage versions of them……
IMO, only the BMW & Merc handle really well (being rwd) so once you’ve compromised on that point, and gone for a fwd estate, then you may as well get the most space / best spec for you money, at which point, a mondeo or Octavia are leading the race!