no, only traditional diamond style frames with an uniterupted (full length) seat tube up to 31.8 in size. Other immobilise products are avalible for other styles of frame.

Yes- it fits in the frame below the saddle

The unit is a plastic plug with flared lugs that is pushed deep down into the seat tube - once in you won't get it out.
Unlike an external serial number, it cannot be scratched off. It has an RFID chip in it - when scanned, it's number will appear on the scanner.

You'll need to ask the local police if they use the detectors for them.

I was told by the London police that the detectors are very big and they don't use them very much.

In Athens.........I really really doubt they would have the kit or the want to check for stolen bikes

Probably not. Folding bike seast tubes are much longer than this device