Ric Gerrad gave me this advice it worked well for me :
HD and HDV are all square pixels. 1440 X 1080 is exactly 16:9 with 1.33PAR. If you are going back out to HDV 1080 then that is the size for your final render comp. For now it will be best to interpret the footage as square pixels and just work in that sized comp unless you have other output options.
If you are outputting to DV PAL widescreen or outputting HD at 1920 X 1080 then you fit the footage horizontally by using the shortcut Cmnd/Ctrl + Option/Alt + Shift + h. with the footage interpreted as square pixels.
The other option you have is to multiply the X scale by 1.33333 for a 1920 X 1080 comp (You’ll see 133.333% for the X scale if you fit the footage horizontally using the shortcut).
If you want to use this footage in a PAL widescreen comp then fit the footage to the comp using the Ctrl/Cmnd + Alt/Option + Shift + F shortcut interpreting the footage as square pixels. That should give you X and Y scales of 71.111% and 53.333.