Financial Appraisal Model

I am revising financial appraisal model for new build and would like to benchmark key assumptions against other councils and private sector. I would be grateful if you could share assumptions made in your financial appraisals model for following:

1. Management cost per property. £600
2. Maintenance cost per property. £600
3. Majors works 0.8% of construction cost starts from year 11.

Thank you.