Go in via front left wheel arch area.... look to the right of the driveshaft as it enters the transmission. There is a 24mm bolt. Fill till fluid comes back out... you will need some tubing and a bit of gravity.
Not sure on V40 but if it has same Ford chassis as S40/V50 you may find it useful to remove the bolt from the lower torque mount and you can slighly pry the gearbox forward to get better access to the fill bolt.
Below is for the V70 but you get the idea...