Video download file sizes

[Clive]

The Hollow Crown, Henry VI Pt 1 is available in many sizes. --info tells 
me that flashhd1 is 1910MB and flashvhigh2 is 1198MB. I have downloaded 
it twice as both versions and they are both the same size (1.3GB) with 
VLC reporting the same resolution (832x468). Can anyone explain this to 
me please and is there a way I can get the higher resolution? I 
downloaded the first four when they were broadcast the first time and 
they are clearly bigger and better.

Thank you.

Clive