Peugeot 207 o/s wheel jumps on full lock

Play in suspension joint or c.v. Joint possibly ,If you can jack that side up and check for play.

check your wheel arch liner

Could be a worn top suspension mount or snapped suspension coil spring have a suspension check carried out at your local garage hope this helps.

As above i would look to see if there is any obvious damage to any thing on that corner like broken spring so on.
as stated above look at your wheel arch and Tyre to see if there has been any contact between the two.
If there is not any thing obvious then would lift car and check for play in the wheel itself hold the wheel in the "half 12" position and push and pull alternately with each arm then do the same at the "quarter to 3" position and do the same, if you feel movement or knock or bangs then source where that is coming from.
if its inside the wheel most likely bearing, under the hub would likely be lower ball joint or steering track rod end and/or link rod, from top of the spring then strut top bearing but depending on how they fit most do have play in them as they sit in strut top mount. If that fails move the steering wheel all way over to one side then spin to see if grinding or knocking if so would probably be CV joint on the drive shaft. hope this gives you some help if all else fails i would go to a good garage and ask for them to look as most good places wont charge for just looking :)