Thanks for the reply mate.
They are full boards, although they will be laid perpendicular to the joists. There won't be anything running along the line of the join. There are few noggins, the only one there to support inspection hatches (which will be fitted too)
Here is a picture.
As you can see, there are only beams with few noggins (two, I believe) The one in the picture is for the gas shut off.
I will be screwing to each joist and at the ends, but I'm not able to fix along the board join.
Ok?
Thanks again for the reply