Hey,
Just a quick reply to say i managed to replace the cicular door vent.
incase anyone has the same problem heres how i did it, it was quite easy to remove.
I just opened the door fully and went through the gap on the inside of the door. I used a phillips head screw driver to hold the screw in the centre of the vent in place and turned the vent its self counter clockwise from the outside and it just unscrews off.
Turned out to be really straight forward and luckily didnt need the door pannel to come off