You can find REAL's 2022 statistical analysis showing the level of compliance with the plastic limits required by PAS 110 (and for compost, the level of compliance with the physical contaminant limits required by PAS 100) here.
The analysis in the paper shows 98.5% of compost samples and 98.1% of digestate samples tested were within the limits for physical contaminants. (Any failures must be investigated to ensure that only material compliant with the limits in the standards can be sent to market.)
In the majority of compost samples, the level of plastic contamination fell below 0.02% mass/mass. In the majority of digestate samples, the level of total physical contaminants (including plastics) fell below 0.039 kg/t.