Flying in ATTI mode is also required here in New Zealand when going for the NZCAA 'Part 102' UAV Operators Certificate. Just going through this process myself - achieving a pass in relevant aviation law and now logging as much time as I can flying my
M2P in ATTI mode before having another go at the practical - flying in ATTI. Nixed my first attempt when I couldn't handle my bird around the course in 30+ km/h winds, which was my own fault as I simply had not logged enough training hours flying both my Inspire 1 and
Mavic 2 Pro in ATTI mode in more challenging wind conditions.
Now, while we all know DJI have not provided that option in the
M2P/Z, it is possible to map the control mode switch on the right hand side of the RC to include ATTI, OPTI and either SPORT or TRIPOD - There is only a maximum of three options with this switch.
Search YouTube for information on how to do this. As a start try, 'DRONE U' "MAVIC HACK: How to get attitude mode on a Mavic Pro". There are plenty of other tutorials, some good, some a bit rubbishy - read up and watch many of them, before attempting to carry out the modification on your
M2P.
If you aren't technically minded the process of re-mapping the three positions of the control mode switch might seem more than a bit daunting, but it is possible. Using DJI Assistant v1.1.2 you won't be "hacking" the inner depths of DJI's binary code, instead you will be modifying the specific flight parameters that DJI can, and do modify through firmware updates. Unless UK laws have changed markedly in recent years, you wont be invalidating consumer guarantee laws either, as remapping the control mode switch is a non-destructive modification, i.e. any changes made to allow one of the switch positions to provide a flying configuration in the ATTI mode can just as easily be reset to something else, or back to its factory setting.
I suggest any changes you make, are first tested out using flight simulator. If you are only used to flying in OPTI mode, mastering the ability to just hover over a given ground reference in ATTI might be a challenge initially.
Good luck, good flying.