Tom Tom direct wiring

[WJNB]

Newly acquired 2016 Mercedes car does not have the console located 12v cigar/lighter type plug which on the previous Mercedes allowed me to hide wires to dash mounted Tom Tom. No way do I want to have to drive car trailing a wire to an ashtray sited plug. Halfords claim to hard wire a Tom Tom but have little confidence that the operative won't cock it up & confuse the electronics ECU etc. Doubt if a Merc.dealer will want to know but hoping an independent Mercedes specialist might. have no confidence to attempt a DIY job .
Like the Tom Tom because of the audible camera warnings & ease of comparing current speed limit to my actual speed - much peace of mind as a result.
Have I missed an option?

[Mr Pointy]

Waze (phone app) displays your current speed if you want to keep an eye on it.