The Q5 was redesigned for 2018. While there is still seat belt overlap between 2D & 2C, the buckles for all 3 seats remain elevated and flexible, which gives greater chance of getting a car seat in 2C and an adult buckling up in 2D. 
The seat belt for 2C is anchored above the bight – which can make the lap belt fit on some adults quite poor as it tends to pull the lap belt up into the soft belly, and off the strong hip bones. The way the seat belt for 2C is anchored can also interfere with achieving a secure installation with a car seat.
The Q5 was first introduced for 2009.
There is seat belt overlap between 2D & 2C – but because the buckles for all 3 seats are elevated and flexible you have a greater chance of getting a car seat in 2C and an adult buckling up in 2D, or another car seat in 2D.
From 2009-2010 the head restraints for 2D & 2P were slightly different – they look like the one in 2C where it protrudes and overhangs the seat back.
If you need to do 3-across in this car, the tricky part is 2D/2C as they are the narrowest seats. With a forward-facing Diono Radian RXT in 2C (installed with seat belt + tether) you can put an IMMI Go (installed with lower anchors + tether) in 2D or a rear-facing-only seat like a Chicco Fit2 or Cybex Aton2 in 2D. With a rear-facing-only seat in 2C (like the Chicco Fit2 or Cybex Aton2) installed with the seat belt, you can put an IMMI Go in 2D (installed with LATCH). If a rear-facing car seat is in 2C, 2P can accommodate a slightly wider car seat – like a Britax Frontier (to keep an older, larger child harnessed) – but if 2C has a forward-facing car seat, best to stick with a narrow seat in 2P like a Clek Foonf (rear-facing or forward-facing will work). When installing a forward-facing car seat in 2C you will need to remove 2C’s head restraint.
