Dont know where the ones go. please help.

The ones are difficult its just guess work!!

SPOILER ALERT:

they go diagonally from either side of the 4s in the middle row, and there is one in each corner of the middle box. I hope this helps Bloggsy.

Too many ones and too many possibilities :(

Thanks for the help Debbie. Its so annoying to get to the end of a puzzle and not be able to finish it.

Thanks, Debbie!!

Thank you, Debbie! Too many ones for me to guess at.

Well, I've finished it but it's another "invalid"
I'm not doing it again as I've tried loads of possibilities!

In the middle there is a plus symbol (+) and the ones make two circles around it

there is a one in in row 13 columns 10 and 16.
In col 11 and 15 the ones are in row 8, 11, 15 and 17. I think this will be enough to help you :-)

Ambiguous middle dots but did with the hints thanks.

Very cool design despite the ambiguous squares. Thank you for the hints Debbief25.