The PY21 and PY21W bulbs are slightly different. The PY21 has the 2 bayonet pins directly opposite, i.e. 0 degrees and 180 degrees. The PY21W has them slightly offset, i.e. 0 degrees and 150 degrees.
The Clio uses the PY21W socket/bulb for its indicators. I am not aware that a PY21 is made in the Silvervisions.
Dave