hole in my brickwork

[ces1]

Hi this is my first post
I bought a house (1880s terrace), with a surveyors report that said "historical cracks" or something along those lines. There's an area in the entrance room next to the front door which had an old crack in the plaster (obviously hasn't been repaired in the past 6 months at least) and which I wasn't too worried about. However, I've had the plaster below it stripped for a damp course, and it looked as though the brick work had "slipped" at some point so that there was a step of around 2 cms. And now I've had some electrical cables put in just above, there seems to be a gap in the brickwork of the same amount. My doors aren't sticking, and there's been no major strucutural work to the house. Also, the rest of the ground floor seems fine where they took the plaster off, and there are no major cracks elsewhere (just a few where plaster's been added over chasing). The mortar between the bricks looks quite dry and crumbly.
Basically, is this likely to be a major problem, and if so, how to I tell? If it just needs fixing, how do I do that??
Thanks for your help in advance - this is my first house, and it's stressing me out a bit.

 

[Aardvark Plasterworks]

No stress. If the removed plaster was original and not filled very much, then it was probably plastered like that.
If it had moved 2cm over 130 years, that makes 0.015 cm per year!
If, however it has moved suddenly then this is concerning, but 2cm still isn't much for a house of that age.
Lastly, the simplest answer is from your neighbour on the other side of the crack!

 

[Bostitcher]

It doesn't sound like its going to be a big problem! I think fault lines move faster than that!