Land mass

[saphire krakens]

Are there any islands in the kingdoms of bretonnia
Its for my army back story

[snowblizz]

None of the armybooks show any significant islands around Bretonnia, though there might be something smaller.
If we extrapolate from "our" world the corresponding regions doesn't have any islands of note. Though there are some small ones, eg the channel islands.

[saphire krakens]

so i could just invent one to suit my purposes

[snowblizz]

Sure, why not.

[IBBoard]

There's always scope to invent small things - minor town, small isles, characters who people haven't heard of before. The only thing to be careful of that some first-timers get a bit crazy on is trying to create your own version of the mega-characters. Creating some new all-powerful character may seem good, but it'll be unbalanced etc. Background is similar - create something interesting, by all means, but don't make it too overpowering and all-encompassing or it'll just feel wrong.