Hard lines!! - Flag lines not straight

[Chungas Revenge]

Am laying Indian Sandstone flags and have put down about 15 sq metres having sorted out my sub base and bedding mixture. Levels are good - correct fall away from house and level across width of patio. HOWEVER - my heart has just sunk - my missus has just looked out of the patio doors and pointed out that the lines going away from the house are not straight. I think I have not left enough space between each flag and seemed to have followed the line of each flag and not a straight line from the house. Is there a way I can correct what I have done without too much upheaval?
Yours hopingly - Chunga

[Suggers]

I would set up a string line at right angles from centre of patio doors to see whats occurring - has bedding mix gone orff yet? -

[Chungas Revenge]

Have used a 1 in 10 sharp sand and cement mix which has been down for a few days now - I havent checked if it has gone off yet as I wasn't sure what to do.

Regards

Chunga

[Tony McC]

I'm late to this thread, but how did you establish the perpendicular out from the house? If you use a 3-4-5 triangle, that gives you a line at exactly 90° to the house, and you can use that to ensure your flagging is square.