Graham
i had a look at the Dell inspiron PP20L the main lap top i am experimenting with modeline screen grab of its settings picture below ...i am not sure if that's enough information on the graphics chip used .
I pretty much just want Composite video ,i don't need an RF modulator .
Not many vintage 405 line sets in Australia,i am sure there's some but can't say i have seen one .
There were tests in the late 1940's Sydney and Melbourne one did 405 line the other 625 line and they went with 625 line in 1956.