Peugeot axle problems

Get this looked at as soon as you can, ignoring it will cause extra wear on other parts pushing the cost of repairs from 'Ouch' to 'Aaaarrrgh!'.
The thump may not be the brakes. Does it thump as bad if you do it in reverse? As the vehicle brakes it's entire weight shifts forward so the most likely cause will be something worn out on the suspension, usually parts like a worn rubber bushing, worn shock absorbers (dampers), or a broken spring. Get all four corners of the suspension checked over as sounds can travel and appear to be coming from a different area of the car.
As to the camber. It should have a tiny amount of negative camber as this helps prevent 'Wheel Tuck'. This is where the wheel and tyre tilts or folds under the vehicle during hard cornering. Tucking can 'pop' the tyre off the rim risking the vehicle tipping sideways and rolling over.

the dealer is having you on
thumps , bumps and the like indicate something worn , loose or ready to go bad quick
it could be lower ball joints, upper control ball joints or upper mount if strut suspension
could be worn rubbers in the stabilizer bar area
Best take it to an accredited suspension specialist shop and have it checked out ( get a quote to fix) before it fails and causes serious damage
if it is serious and costly get a report and then front the dealer for the cost of repairs or talk with a lawyer

I would have the rear suspension rubber isolation bushing checked for wear.

I have a bmw x3 that is making a banging noise when slowing down or crawling in traffic. it has just passed its mot had new front brakes and handbrake.
has any one experienced this or can help me to solve this problem.

first of all, since you are using adjustable suspension you should make sure the spring is captive in the shock absorber. Lift the rear of the vehicle and support the car on the body, allowing the rear wheels to hang down. See if the spring can easily be moved. If it can. then likely the spring has sagged, or it is incorrect for the shock absorber. If not, while you are there check that the top hat of the strut is tight by lifting the wheel and strut assembly by hand. If you get any movement in the top of the strut, there will be a loud noise while going over bumps. Another area to check are the stabiliser arm/sway bar bushes. Mounted to the body you will see a bar that goes left to right, connecting to the struts with small link arms. Try to move this bar up and down against the body, paying attention to the rubber bushes where it meets the body. If there is movement in the bushes, there will be banging sounds when going over rough surfaces or bumps. Also check the small link arms for looseness or play.

The clicking is the halfshafts or front wheel drive axles. I have a hard time believing that they have went bad already but anything is possible. The banging noise is something in the suspension, perhaps struts or a sway bar link.

Could one shock be bad? Causing a difference in bounce return rate? I would crawl under suspended car and check all suspension bolts. Are your bushings in good shape? If one is chewed up or missing then this would cause that misalignement. What kind of suspension do you have? Solid axle or independent susp? I don't know if your car is front or rear wheel drive. I'm guessing front wheel drive.

It could be wheel bearings, jack the rear wheel up and grab the top and bottom, wobble it, and if it wobbles alot, then the bearing has gone, or you may just need to grease them up.
It could also be susoension bushes( rubber or nylon inserts on the bolt points ) again, jack the rear up and look at the bolts that hold the suspension on and wobble the components to check if they move too easily( you will always have a small amount of freeplay ) REMEMBER TO USE AXLE STANDS AND CHOCK THE FRONT WHEELS WHEN WORKING UNDER A CAR, EVEN WHEN ON AXLE STANDS you don't want a tonne of steel pinning you down.

Check sway bar. On some models as suspension sags, sway bar outer ends will contact the body, leaving a mark or dent just above the end, causing a bang over bumps. Only way to correct this is to change springs or add a spring lift.

check to see if the struts mounts at the top are good and they are not leaking any oil and also check the wheel bearings