For anyone that might find it useful to know I got the repointing done and the cracked brick replaced. Since the cracking appeared around July 2017 there was no further progression of the cracking. During the long hot summer of last year I was keen to see if further cracking would happen but nothing happened.
During the removal of the mortar where the cracking was it was noticed that the cracks didn't go all the way back through the mortar meaning that the bricks were still joined which I thought was interesting.
I also managed to look up I into the roof space taking pictures with my phone after the soffit was removed. No cracking evident on the inside wall.
Hopefully all fixed but will in the short term keep an eye on it.