WiganWarriorsFans.com

Did a quick scan through pre-lockdown results. For each team we played, I compared their average pre-lockdown score against other teams with their score against us.
[So a negative result means they got less against us than their average v other teams.]

War -7.7
Cas -6.8
Tor -2.5
Hull -10.1
HKR +2.4
Sal +5.3
Hud -9.0

Overall, these do support the idea that our defence is better than average, or was pre-lockdown.

Post-lockdown scores give quirky results:

HKR +20
Cas +8.3
Leeds -15.7
Wake +22

Wakefield scored 22 against us, and 0 in their other 2 games! The sample size is not big enough to draw conclusions, but 3 out of 4 teams scored more against us than their average score.

You'd need a full season to draw conclusions - just by comparing the "points against" columns - simples!