Ok,
Creating a new drawing didn't work. What I have worked out is it will do it on any of the layers with my non-standard linetypes. ---Telco---, ---SW--- etc.
Not sure why this is. Therefore if I set my layer to continuous the block will insert correctly. Further to that if I change that layer back to....---Telco---, then the block inserts correctly. Or if I run a bat routine to load another profile then set my profile back <<unnamed profile>>. Anyhow the profile change has fixed my problem for the time being. This is not the first time I've tried to fix this. I understand it's nigh on ..... if you can't emulate it your system.
Damian.