Bluetooth without MFSW or touchscreen

Hi all, I'm seriously considering retrofitting an original bluetooth kit to my yeti, but I don't have a MFSW nor maxidot and my radio is a swing model, so no touchscreen.

I asked the seller how I could answer or make new calls, and he told me the only way is to intact with the phone itself. Though this could be acceptable, I was wondering if there is a way to (at least) answer calls using the switch on the right lever. Also, what happens when the phone sends audio via bluetooth (I use the phone as a sat nav) but I'm listening to something else, let's say a cd o fm radio? Would the bt audio be played or simply be ingnored?

The other option, instead of going for a VW bt kit, would be to buy a third party kit which is said to be skoda official, although it's clearly manufactured by bury, something like the 5J0051473A (http://www.superskoda.com/Skoda/SUPERB-II/Yeti-bluetooth-handsfree-system-original-Skoda-Autoas) which has dedicated buttons and can be operated independently. Anyone has ever tried it? Is it good or there's a reason why it cost nearly half the price of the original VW kit?

Thank you!