Well I thought that I would post this so others might benefit from my experience.

History: Stream MP3 swapped for Bolero from 2011 Octy. Aux input in centre armrest worked with my Sony Walkman NWA-865, so I foolishly assumed it would work with the Bolero. It didn't.

1) The actual swap of the headunits is fairly straightforward. Access is quite tight but removing the cubbyhole on top the dash makes no difference I found. To remove the Stream HU make sure and get your finger(s) right under the antenna and quadlock connector and flick the levers upwards to release.

2) Lots of research on the forums. As recommended by my-gti.com I purchased the 12 pin green connector from Skoda dealer ( £6, plenty in stock)

3) The wiring in my 2008 Octy was different from that stated in the article on my-gti.com. Not sure why; were they talking about vRS Octy?

4) Use the end of a straightened paperclip to push into the slots of the blue connector then pull on the wires to remove. Don't keep pulling on them like I did!! Skoda engineers are very sensible people.

5) After all this ready to plug wires into new 12 pin connector I realized that the new Bolero HU did not have all the pins present, including the necesary pins 1,2 and 7. Tried pulling out the other pins but they were fixed pretty well and I thought I would do some real damage.

So endeth the lesson. Not sure why not all pins present; it may be a random thing. If you are swapping your Stream for a Bolero you will lose the Aux input, and getting it back is not guaranteed.Its a shame because the Bolero is such a nice HU. Ah well, Dension or Skoda MDI anyone?

it should be possible, look at the pin diagram on the sticker attached to the Bolero, and from there you simply need to connect to the appropriate pins instead. Are you sure pins 1,2 and 7 were missing?.

I swapped my Stream MP3 for a Bolero no problems, all worked great.

It is possible to disable the AUX port on a Bolero though. (I'd tell you the settings, but I changed my Bolero for something else a couple of months ago)