wobbling

Hi, I have a 2010 seat ibiza fr 2.0 I have a slight problem when turning at slow speed (20-40mph more or less) when in the turn the steering feels like it has a slow wobble like side to side but slow like if the tyres where wondering side to side it’s hard to explain, any ideas of possible...

We have a builder who has added a damp proof course and then added bricks on top. Should the bricks above be fixed in place or be able to move? At present the whole wall moves at the slightest touch above the damp proof course. It is not complete, but we don't feel this is right. We are talking...