So I caved and put in Dad's name and now have thrulines. I have a few things to investigate but have noticed something weird.
Thrulines lists all ancestors and if you click on them it shows if there are any matches who also have them as an ancestor however it has missed out one of Dad's great grandfathers and one 3g grandfather and I know there is at least one descendant of the 3g grandfather who had done a DNA test. I had expected to be told there were no matches for the great grandfather but I didn't get that, he just doesn't exist. I did get told there were no matches for Unknown, his 2g grandmother, so I'm finding it a bit odd and clearly the matching isn't exact yet. It also uses trees where there are no DNA matches for anyone who hasn't tried it yet.
However, I think one of my brickwalls may have the wrong wife so I am off to investigate. Hard to deny I'm wrong when there are DNA matches to a 5g grandfather I'm don't think exists.
For those who are like me and don't want to put names of living people try using a fake name. I think they just need a name to get it started.