Its off course nice that you provide it while server is down, but you probably understand that there is quite good reason to ask users product code before downloading? So Please put in your orginal message that any other users outside UK should not test your file.

I do not know what difference there is between firmwares, but I would be very very very careful with these things. I would not be suprised if there is different firmwares (gsm firmware) between countries.