No, Tora, the definition in the relevant law is specific. The item is defined in terms of it being a device for communication, and therefore communication is the mischief at which the law is directed. If the defendant was holding a tape recorder, or a camera, and using that, there would not be a specific offence; no law provides that using a hand- held recorder or a camera when driving is an offence. It follows that if a camera has a phone, or vice versa, or a phone has a 'Dictaphone', or vice versa, and those functions are being used instead of the phone, the communication function, the offence is not established. That view is reinforced by the law being written to meet the possibility of someone emailing or texting by some hand -held device, on the assumption that such a device is not a phone or is a phone not being used for vocal communication. If Parliament wanted to ban the use of all phones, whatever gadget or extra built in, was being used ,it could have said so.
The answer would be to reframe the law, or redefine it: a search does not suggest that that has been done. Every source is the same.
You could be convicted of another offence, such as failing to have proper control of the vehicle, but not this specific one.