Do Not Sqwauk 7700.....
....are you in immediate, life threatening danger? No? Didn't think so.
The one thing that nobody has mentioned here, and it's sooo easy is the traditional VDF call.
If you look at your VFR chart here in the U.K. you will note that certain aerodromes have the initials VDF next to them. Tune in and ask for either bearings or steers (magnetic or true - up to you)
They will usually give you a bearing from the station - which you can then cross cut with a station you think is at 90 degrees. You can find which stations will work for you as you plot your route.
The full description of the process is detailed in CAP413. No gadgets required.
As SoCalApp has said, I am extremely surprised that your instructor has not covered this with you at some length, and you should have been tested on this by your examiner.