Finally got around to do a post . After long research I decided to go for double din DVD unit ( Pioneer AVH-270BT  in my case ). So first of all-  it is possible to fit it in standard Ford 1.7 din hole  . Thats what I had:

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1. Remove old unit and make sure you have all wiring adaptors you might need .
2. Once old unit out you will see a lip around hole, I used multi tool to cut top and bottom lip off . Hacksaw should work as well:

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3. Feed neatly all necessary wires to the unit (camera .USB.microphone )
4. Now clip all wires in place and slot head unit in place and lock it in place (I used screws between trim and head unit body )
5. I used strips of washing machine drive belt to fill gaps on sides :D :D. Someone might have better idea ...
That is what I have now.

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It was nightmare to run camera wire to boot lid ??? . I fed it under rubber seal , tucked it under rear trim panel  and threw rubber thing into the boot lid . Now a few things:

There is no need to use a mounting cage or head unit bezel
Motorized units will not fit !!
Body of head unit has to be 100mm high and front fascia (not bezel) has to be 100mm high as well .