Airbrick below new patio doors and ventilation

[richie9648]

Hi

I’m having new patio doors fitted. Currently there is an air brick on each side of the property (extension) ducted through to the suspended timber part of the house.  For some reason also they have been fitted at ground level. 
 

I am having the doors fitted flush to a new patio area and fitting an ACO drain at the edge. 
 

Will there be sufficient ventilation - can air pass through the bricks and out the top of the ACO drain or am I compromising the ventilation here? 

it’s a little bit like the pic in the link below but the airbrick is below the door and I’m looking to raise the patio upto level of the door

 

https://www.diynot.com/diy/threads/patio-half-covering-air-bricks.572322/