There is a hole directly below it, which on my bike was plugged with a cheeseheaded screw. This is it without the screw blocking the hole:-
Now, I can't really tell if its breathing through this hole with the timing cover open. I poked a wire up the hole and there wasn't anything blocking it. Refitting the timing gear and sealing the case and I can hear the engine beathing from the hole - wonder if it'll make any difference. Only time will tell.
Timing cover and cams:-
I also replaced the Brammer belt with the T-link belt I used before.
My garage is too full:-
One you drink, one removes gaskets - you choose.
A 1913 gearbox:-