The plate number appears about centrally in the vertical frames. This picture is not good enough. You need a good scan to show it. The same goes for your other post. That may proof difficult as the cancellation obscures the parts where the plate numbers appear.
I do think GeoffHa is correct, but it really needs a clearer scan.
Scan. An Iphone takes pictures. You will need a (flatbed) scanner with a good resolution (600 x 600 dpi or higher, usually does fine). Pictures become too blurry. Also, if you use flash or have a lamp near that mount, you will see a reflection of the light, instead of details.