[Q] Lenovo A806 and voice commands topic

I have just purchased this phone from China, kitkat 4.4.2, which has the ROM VibeUI-V2.0_1447 . . . DEV_A806. Whilst this ROM can be found on needrom I suspect it is not official but a custom ROM for ROW use. The problem I have is voice commands seem not to work and I cannot find out how to activate them. For example the dialler has no facility to activate voice, and when paired with my hands-free car device no voice commands work. Is there some setting in kitkat to sort this, or is it a ROM deficiency?