Concerned about my brakes!

Alright chaps, i've been ignoring this for a while (pretty much since i bought the car) but it really doesn't feel right at all....

When i'm going along at say 30mph and above and i apply the brakes, or have the brakes applied while going over a bump in the road there's a very unnatural feedback through the pedal. It sort of feels like the pedal depresses a bit more and jolts sharply. Not a confidence inspiring sensation!!
Has anyone else had this? Is it 'normal' for A3/S3's to badly feed back through the brake pedal like this when going over bumps with the brakes applied??

If this isn't normal it definitely needs looking at....I don't want my brakes failing, lets be honest!

The car is due in for it's service and so they can look at the knackered air con. Maybe this is another for the list?!

It's whenever the brakes are applied and i go over a bump, it almost feels like the brakes get knocked out of place or come loose. Hard to explain really. It's not a juddering sensation like with ABS, it's more of a harsh thud. Anyway why would ABS be kicking in under average braking pressure at 40 mph?

I'm guessing other than ABS 'judder' there should be no feedback like this surely?