Filling holes in basement wall

[aweste00]

I have removed two old steel pipes for oil filling to the oil tank that were located next to a ventilation duct. How do I fill the space? That is, the one on the left, the ventilation duct should remain!
Should I cast? Bricklay with bricks or similar?
I understand that the outside should be plastered. The hatch in the brick is from the air vent of one of the pipes.

 

[Småbrukaren]

If you get hold of some old bricks, you can chip out fitting pieces that you attach with mortar, and you can use chicken wire as reinforcement to keep it in place. It doesn't need to be particularly neat since you can seal and smooth everything out with a few thicker layers of plaster or house fix at the end.

 

[aweste00]

If you get hold of some old bricks, you can knock out fitting pieces that you attach with mortar, you can use chicken wire as reinforcement to keep it in place. It doesn't need to be particularly nice since you can seal and smooth everything out with a few thicker layers of plaster or house fix at the end.

OK, thanks! I've found a brick that I think fills up 75%. Too bad I threw away a meter of chicken wire this spring...