Incorrect Progressive / Interlaced Flag

[Black Hole]

I've used a video grabber to digitise the output from a VCR. The resulting .mpg plays the audio OK, but the video is sped up (maybe double?), in both VLC and VideoReDo.

MediaInfo says:

===================== General =====================
Complete name               : I:\AV\Video\Elizabeth\DVD_154843_0.mpg
Format                      : MPEG-PS
File size                   : 4.10 GB
Duration (ms)               : 1h 11mn
Total bitrate               : 8 204 Kbps
Encoded library             : honestech

===================== Video =====================
Id                          : 224 (0xE0)
Format                      : MPEG Video
Format version              : Version 2
Format profile              : Main@Main
Format settings - BVOP      : Yes
Format settings - Matrix    : Default
Format settings - GOP       : M=3, N=12
Duration (ms)               : 1h 11mn
Bitrate                     : 7 816 Kbps
Bitrate maximum             : 8 000 Kbps
Width                       : 720 pixels
Height                      : 576 pixels
Aspect ratio                : 4:3
Framerate                   : 25.000 fps
Standard                    : PAL
Colorimetry                 : YUV
Colos space                 : 4:2:0
Bit depth                   : 8 bits
Scan type                   : Progressive
Compression_Mode/String     : Lossy
Bits/(Pixel*Frame)          : 0.754
TimeCode_FirstFrame         : 00:00:00:00
TimeCode_Source             : Group of pictures header
Stream size                 : 3.90 GB (95%)
Source_StreamSize_Encoded/S : honestech
Encoded library             : honestech
colour_primaries            : BT.601 PAL
transfer_characteristics    : BT.470 System B, BT.470 System G
matrix_coefficients         : BT.601

===================== Audio =====================
Id                          : 192 (0xC0)
Format                      : MPEG Audio
Format version              : Version 1
Format profile              : Layer 2
Duration (ms)               : 1h 11mn
Bitrate mode                : Constant
Bitrate                     : 224 Kbps
Channel(s)                  : 2 channels
Sampling rate               : 48.0 KHz
Compression_Mode/String     : Lossy
Video_Delay/String          : -40ms
Stream size                 : 115 MB (3%)

===================== Menu =====================

What stands out is "Scan type = Progressive". It should be interlaced! I guess that would double the frame rate if fields are taken as frames.

Anybody know some magic I can use to change the scan type info?