OK, one downside to venting the breather to atmosphere is the smell! When sitting at idle you can smell the fumes coming into the cabin, so after using my brain a little I came up with this to see if it would
help.
Take one old spray paint can lid:
Cut a hole in it to push-fit onto the base of the filter:
Perfect fit! It extends beyond the end of the filter and allows room for it to breathe whilst hopefully shielding the fumes and forcing them downwards:
Fitted back onto the tank:
How it looked beforehand:
I am pleased to say it has made a big difference, all I get now is the tiniest of whiffs at idle, compared to before it is very slight - so it's a success!