You have a .22" No8 rifle backsight on your rifle! It was upgraded to Mk1/2 standard (from Mk1 spec) at Fazakerley in Liverpool in October 1949. Can't tell where it was originally made though. Looks like there has previously been an optical sight fitted by the screws in the breech ring.
To get any further info we'll need to see the left body side and butt socket