Fitting leather seats advice needed

Just bought second hand S-line leather interior for my audi a3 2010 8p 2.0 tdi sports back.

They are heated and have electric lumbar support, has anyone had experience of fitting these? I have bought the heater climate control switch panel for heated seats which will obviously replace my current switch panel. I also understand I need a seat heating harness wiring loom which goes from the heater control to the seats. I am currently in email exchanges with kufatec.com German firm regarding purchasing this.

Its probably not something I want to take on myself, do you suggest using a car interior upholstery fitter, a normal car mechanic or an auto electrician?

From what I can gather on YouTube fitting the actual seats doesnt look a problem, its just the heater and wiring that looks tricky.

Any advice appreciated.