But if I set the TV to 16:9, the picture is stretched.
As spiderplant suggested (thanks

), I ran a SCART lead from the V+ VCR/DVD output to another TV. This confirms that the signal transmitted from this output is 14:9.
So that eliminates anything to do with the DVD recorder (for now...

).
So, if the V+ box is connected to my TV by HDMI, and the TV Display Format is HiDef HDMI, and the V+ Box HiDef Output set to 1080 Wide (which seems to be the correct setting for my TV), what aspect ratio would I expect to get from the VCR/DVD output? Is there a separate setting for it?
UPDATE: I phoned Virgin Customer Services who told me that it's not possible to change the aspect ratio setting output by AV1, but it seems illogical to me that a facility is provided to copy a recording to VCR/DVD, but if it is 16:9 widescreen, you can't copy it in it's original format?