The issue with sickness absence in civil service as a whole is that it’s roughly double private sector, why because majority get 6 months full pay & another 6 months half pay so no incentive to return. Monitoring and disciplinary action against constant abuse is minimal in public sector, in private sector you would undoubtedly be managed out.
This excludes genuine long term sickness for cancer, major operations etc. too many I’ve injured my back, leg , hand so unable to work but ok to go on holidays etc