Surely that is £1500 per residential property in vouchers and top ups?
For residential property - £1500 for rural gigabit voucher and £1000 for KCC grant which equals £2500 per property
For a business Property - £2500 for gigabit voucher and £1000 from KCC grant which equals £3500 per property
You can mix and match gigabit vouchers with rural gigabit vouchers