This is what I have found so far:
Picture showing a Hurricane IIc Trop with Vokes Filter, Caption is "A cannon-armed Hawker Hurricane IIC based on Malta revving up before taking off to tackle an incoming Axis raid. This picture shows the air intake under the nose very clearly.":
http://www.historyofwar.org/Pictures/pictures_hurricaneIIC_Malta.html
Picture showing a Hurricane IIc Trop with Vokes Filter, Caption is "One of the Hurricane Mk IICs which arrived on June 27, 1941, in Operation Railway I seen at Ta' Qali soon after it landed, (...):
http://ipmsmalta.forumotion.net/t1475-malta-s-hurricane-mk-iic-looking-for-photo-paint-scheme#22029
No other real pictures of Malta related IICs so far, but lots of drawings and paintschemes around.
The funny thing is that while all real pictures seem to show only IICs
with Vokes filter, it looks like all drawings and paintings show them
without.
Both versions are as easy as each other, the question is which one is historically correct.
One could argue that since the Hurris for Malta were initially meant to be for North Africa, they will likely have been equipped with Vokes Filters.
On the other hand, if maintenance removes cannons to save weight, wouldn't it make sense to remove the Vokes Filter too?
And is this feasible at all?
Was the Vokes Filter detachable or would they have had to replace the whole cowling?
Best regards - Mike