The 2013 Civic 1.6 I-DTEC (mine is 2014) HAS indeed a serviceable fuel filter. It's not visible, at least from above the engine bay. It can be reached under the car, but it's not an easy task.

There you were, about to choose the 2.2 i-DTEC that, so far, has been the only diesel in the range. But now, in search of reduced emissions and fuel savings, Honda has added a 1.6-litre diesel
Fuel Consumption. Any 17. 30+ mpg 17. 40+ mpg 17. 50+ mpg 7. 60+ mpg 7. Colour. Any 18. Black 3. Blue 3. Brown 2. Grey 1. 2014 Honda Civic I-DTEC SE PLUS TOURER
Honda Civic X Edition 1.6 i-DTEC (120 Hp) Hatchback 2016 2017 2018 2019 | Technical Specs, Fuel consumption, Dimensions, 120 Hp, 207 km/h, 128.62 mph, 0-100 km/h: 10.5 sec, 0-60 mph: 10 sec, 3.7 l/100 km, 63.57 US mpg, 76.35 UK mpg, 27.03 km/l Honda Civic 1.6 - Fuel consumption - bad or just normal?. I swapped from a 2000W 1.0 Yaris over to a 2004/04 1.6 Civic back in March. Since then I've been quite disappointed with the fuel consumption, getting around 35-36 on average for my normal travelling and no better than 38 even on a long run.
The 1.6 9G is certainly noisier than the 2.2 8G when idling. It was my first comment when I got in it for the first time for a test drive. The 1.6 sounds far more more agricultural in the cabin than the 2.2 did. Maybe the 8G had more insulation I don’t know but the 9G is certainly noisier!
CAKNq. 183 383 124 152 260 364 273 296 217

honda civic 1.6 i dtec fuel consumption