There is a setting in EXACT to choose how the acceptance date is picked up:

Go to, Configure, Practice Settings

'The acceptance date is taken from the earliest:

• Completed Item

• Planned Item'.

By ticking 'Completed', the acceptance date is taken from the first item ticked and charged on a COT/
By ticking 'Planned', it is taken from the date the item was charted.

For NHS Practices, this should be set to completed.