Why might my ceiling fan have been disconnected?
Lookin at the photo, it isnt a clean cut so i wonder if it had snapped.


Not a chance. Cables don't snap easily. And they don't cut easily either, which is why the cut isn't clean.


  Can anyone think why this might have disconnected?


My best guess (and it's only a guess) is that the fan was installed by a DIYer, without getting Part P sign-off by an electrician, and in advance of selling the house the DIYer/vendor disconnected it (with extreme prejudice) as they didn't want any liability for it.

(The buyers of my last house may have come across a few similar things...)


  If not, does anyone have any tips how to reconnect with the wire being so close to the wall?


It may be possible to connect to the existing short wires with crimping. Might be worth talking to your local electrician for this.

Or you may be able to use this short wire to draw-through a new longer cable (although I'd guess the friction would probably be too high, and you'd risk stripping the new cable on corners.... On second thoughts: please don't try this idea).

Or you may have to bash a hole in the wall further back along the cable, in order to joint the cable somewhere where there's enough slack in the cable.