[olliej]

What do you mean by access the data?

Activation lock effects the ability for the phone to be set up (e.g. activated).

Actual data on the phone is encrypted to a set of keys, that are themselves protected by the SEP, which checks the passcode, does the timer enforcement, and increments counters, etc.

The moment the device is reset/wiped the keys are gone forever and the data cannot be recovered (even if your took it apart and read the flash directly)