The area in the first pic is immediately above the second.
I've actually solved it though:
Starting from the centre of the joist, I drilled two holes (which meet regs in terms of their distance apart) downwards at 45°. Then chased the wall upwards and brought the pipes out.
Cheers!
I need to bury two radiator pipes in a downstairs wall, but there's a ceiling joist flush against the wall.
The joist in question is pictured. Given that there is barely any load, and it's only 30inch in length, could I notch it at the bottom?
I assume this joist is attached to another joist...