http://www.imcdb.org/vehicles.php?make=land+rover&model=series

pulls up a different list to :-

http://www.imcdb.org/vehicles.php?resultsStyle=asImages&makeMatch=2&make=land+ro- ver&modelMatch=0&model=series&modelInclModel=on&modelInclChassis=on

Shouldn't ones in first list have xx" in front of series to correct?

http://www.imcdb.org/vehicles.php?resultsStyle=asImages&makeMatch=2&make=land+ro- ver&modelMatch=0&model=series+2&modelInclModel=on&modelInclChassis=on

brings up a car! s/b series ii not "2"?

The one with "2" was an error, it is fixed
About the first link, those without a chassis-length are those for which that length cannot be identified, I guess.

Cheers.