Step cracks in outside mortar - cause for concern?

[MrBosch]

Hi everyone, would really appreciate some views on the below pics to my untrained eye. Bit of background. It's a 1930s semi, the mortar in question was repointed before we took ownership in 2011, I'm guessing early 2000s. The crack runs only in the mortar from the downpipe near the bottom right of the window to the black vent in a zig-zag step fashion. This is the only crack in the mortar I can find having gone around the whole house and this is this part of the house that has been repointed - this side of the house gets the weather. The only reason I noticed it was a walkaround as we are selling the property. There's a very fine and small crack on the inside plaster that corresponds with the outside (I could be wrong). I can't be entirely sure if the hairline crack is new, but I don't believe they are as I really had to look for them. The survey we had in 2011 didn't pick up anything significant, apart from the house had some movement in the past but nothing recent and completely normal for a house of this age. My best guess is the newer mortar is cement based and the old mortar is lime based so less accommodating. So any reason to be concerned as I'd hate this to be an issue on sale.

 

[foxhole]

If it is picked up by the Home survey it will just be labelled as a settlement , not a concern.Settlement can occur at any time, often after prolonged dry spells especially over clay .

 

[tell80]

Its well known that settlement typicaly occurs in the first years after new build but in the pics theres been repointing you say was done about 20yrs ago and the stepped cracking has come through the newish pointing so some kind of cracking has taken place in the last 20 yrs.

Both cracks are at roughly the same height and below theres what look like two cracks in the bed above the brick arch - all this in a specific area thats been patch pointed.
Maybe the arch is the culprit?
Maybe it was pointed before the last sale to hide the cracks?

Youve got cavity walls so why the crack on the inside i dont know? Seasonal thermal cracking?