Nina B112 (nrf52) NFC pins as GPIO

Hi,

I am using the Mbed online compiler to write an application for the nina-b112 module that is based on the nrf52 chip.

By default module pins 28 and 29 (nrf pins 9 and 10) are set to NFC functions.
I cannot find any documentation directing me on how to use these as GPIO. I have tried the standard DigitalOut pin definition but this does not work. From what I understand other ides do not have this issue and it appears to be something within mbed OS.

Many thanks for any help.
Calvin