From ETSI Guidance Note EG 203367, section 6.1, when non-radio products are combined with a radio product:
If the manufacturer of the combined equipment installs the radio product in a host, non-radio product in equivalent assessment conditions (i.e., host equivalent to the one used for the assessment of the radio product) and according to the installation instructions for the radio product, then no additional assessment of the combined equipment against article 3.2 of the RED is required.
For the WLR089U0, the European Compliance requirements were tested using the antennas listed in Table 1.