LoTSS major axis physical sizes (deconvolved) vs ${\overline{\sigma }}_{[\mathrm{O}\mathrm{I}\mathrm{I}\mathrm{I}]}$ for the (a) low redshift (0.02 < z < 0.4) and (b) high redshift (0.4 < z < 0.8) sample. The different colours show the peaked and non-peaked spectrum sources. Sources unresolved in LoTSS are marked with a horizontal arrow since the sizes are upper limits in these cases. Dashed and dashdotted lines show the median values for the peaked and non-peaked sources respectively, in bins of major axis sizes. The dotted horizontal line marks the ${\overline{\sigma }}_{[\mathrm{O}\mathrm{I}\mathrm{I}\mathrm{I}]}$ threshold for classifying the [O III] in a source as disturbed.