Is this subsidence?

Hello.
We have just put in an offer on a house in north wales which has been accepted. It does need some work internally, which I can handle, but can anyone tell me what’s happening to the brickwork – please see pics below: You may have to enlarge the pics to see. They are dropping down in one section.

Many thanks.

Looks like a very small area to be subsidence but its possible, looking at the pic even the paving slab seems to have dropped in that area, I would be more inclined to guess a collapsed or leaking drain undermining that area of the foundation.
I would be digging that bit up to investigate before I bought it, is this the only area of concern ?

only area of serious concern to be honest, there's some damp inside but appears to be condensation rather than anything. Do you have any idea of repair cost, should it be what you said?

Many thanks.