If you have an engineers supplier or fastener suppliers place in your area they should be able to fix you up.
The size is 4mm x 0.7mm pitch (standard metric course thread), counter sunk screw 12mm long.
If you can only get longer screws you can always cut to length and clean up the end of the thread with a file etc.
If your struggling send me a PM with your address and I'm sure I will have some I can cut down and send.