The Government's Section 19 and 22 Permit recommendations for vehicles under 10 years of age state: 'bearing in mind that passengers are to be carried in your vehicle and possibly a number of different drivers used, you should carry out more frequent safety checks. DVSA recommend that inspections are carried out at least every 10 weeks.'
If a vehicle is 12 years or older or covers high mileage, inspections should be carried out every 6 weeks
Read the full Government advice here in Section 11.3
Safety Inspection details on the Section 19 Permit application
From May 2021 the application form for the Section 19 Permit requires you to evidence your Minibus Safety Inspections and provide details of who is carrying out the maintenance on your vehicles. You are required to submit supporting evidence that you are having this maintenance carried out.