I've never played a Seagull but I've heard they're a great value.
The scale of a guitar is the distance between the
nut and the
bridge. This goes for other stringed instruments such as Violins or Basses, too. The bridge is where your strings first pass through when you're stringing an instrument and the nut is that little slotted thing that the strings sit in before being wound in tuners. I'm sure there's a better way to put it but I'm lazy so here's a diagram if you need reference:
Right, so to put it more simply the scale is basically the length of the part of the instrument you play on. Standards are 25.5in (Most Fenders and fender-styled guitars as well as acoustics) and 24.75in (typical on Gibsons and Gretches). My martin mini was 23in.
A shorter scale means notes are closer together, which if you have small fingers makes it easier to do complicated chords. Smaller scales for bigger-handed people can be tricky because then they might feel a little cramped. More often than not anyone can adjust to playing any scale of an instrument, I just learned to prefer smaller ones. My friend is 5'2 and she plays a full-scale bass with no problems.