Actually, this is a big discussion in our airline as well(another Dutch company). The initilal guidance in our manual when we first started flying RNP approaches was that you did have to correct the DA for low temperatures, even though you were within the temp bracket to fly to LNAV/VNAV minima. I did some research and have found several documents backing this up.
However, as a previous poster already posted, since 2016, EASA guidance states that when above the minimum temperature stated on the approach chart, temperature corrections are not to be made to the DA, even though the temperature is below 0!!