Just to note.
I would completly ignore all instructions from the CAA and turn my mobile phone on in the case of radio failure. And phone my home tower. They can then contact DnD and get them to ring you back.
BTW this occurance of all your primary glass data going up the swanny is a relatively common occurance in some larger aircraft if you are flying near rain clouds. The static can get to them and then the whole lot throws a fit (three times in 800 hours which is high for any fault in my limited experence). Auto pilot kicks out captain starts swearing because he has to fly it on backup instruments. Once your away from the source of the static it reboots and everything comes back online. First time it happens its a bit of a shock and sods law makes it happen just as you get put on vectors by the director in IMC. And the whole data bus goes, so no AHRS, no air data computer, no stall protection, and 4 screens which flash on and off and look remarkably similar to the test mode with all the warnings up. It takes about 3-5 mins for everthing to get its life sorted.
Our backup instruments are a bat backed up AH with ILS guidance and a pressure driven ASI and Altimeter. Just have to hope your with a radar service and get timed turns for the heading or run a GPS track.