It can be done, although BT dont make it easy (Ridiculous really, as these are designed to be wall mounted)
I used two flat blade screwdrivers, and slowly prised the top off. It does damage the plastic a bit
For your information, I have spent a long time trying to figure out how to re-attach the feet if they become detatched after dropping or manhandling the wifi disk.
The problem is that the internal circular fitting inside the underside of the disk becomes detached from it's mounting. The only way of fixing this is as follows:
1) carefully prise off the front of the unit using a flat-head screwdriver;
2) remove the circular fitting and attached metal spring;
3) ensure that the spring is clipped to the circular fitting using central sipot and integral clips;
4) very carefully insert one end of the metal spring up through the tiny hole and hold it carefully to ensure it remains under tension (otherwise it will fall off and you need to start again);
5) rotate the circular fitting until both legs clip through the circular hole in the bottom of the unit;
6) once you have done this the circular fitting should rotate back under tension to it's correct position;
7) the plastic leg should have two clips which attach to the underside of the circular fitting. They have a push-fit to the fitting. Set the leg in the correct (extended) position and gently push the leg until it clicks into place; this may take several tries - the fit is very fiddly. Do not use excessive force or this may break the plastic;
😎 replace the plasic cover of the unit. There is a fitting hole and clip at the top of the unit which marry together to position the cover. Once the cover is in the right position, push it gently to replace it until it clicks into place.
I hope this post is helpful to this forum.