sources in the 10C catalogue and the simulated catalogue are matched to the Data Fusion catalogue, taking all matches to the radio sources within 30 arcsec. Note that the full 10C sample is matched here.[]{data-label="fig:matches"}](separation-eps-converted-to.pdf){width="\columnwidth"}

![image](10CJ105527-test-eps-converted-to.pdf){width="7.5cm"} ![image](10CJ105107+575752-eps-converted-to.pdf){width="7.5cm"}

![image](10CJ104718+593247-eps-converted-to.pdf){width="7.5cm"} ![image](10CJ105054+580943-eps-converted-to.pdf){width="7.5cm"}

The different catalogues were matched using the <span style="font-variant:small-caps;">topcat</span>[^2] software package. The density of sources in the Data Fusion catalogue is high compared to the potential error in the 10C source positions ($\approx 6$ arcsec) so we therefore use the more accurate positions from the lower frequency radio catalogues (typical error $\approx1$ arcsec). When there are several positions available for a source, they are used in the following order of preference: FIRST, GMRT, BI2006/OM2008, WSRT, 10C. For sources which are resolved into multiple components in FIRST or GMRT, the position from the 10C catalogue was used instead as this gives a best estimate of the centre of the flux. For the three sources which have two separate components listed in the original 10C catalogue (see Paper I for details), the average of the two 10C positions is used.

The match radius needs to be chosen carefully to avoid false matches while still maximising the number of real matches. The 10C sources 