how can I stop the sqeals and bangs?

It may well be a pressure wave in the pipes - you can see an example of this when you sit in a bath of water. You make a wave that travels up to the end of the bath and when it gets there the water rises up but the energy is not fully dissipated and a wave comes back towards you. This may be happening in your pipes. It will cost you nothing to close off the house stop-tap a little (or even a lot) and see if you can make the noises quieter or go completely.

Peccavi
October 2009

The clang of the pipes is due to the pipes themselves not being adequately clipped to the surrounding woodwork or walls.....when the pressure changes, the pipes move a little, causing this characteristic clunk. This will be worse when its taps etc in your house causing it when they close but to a lesser extent it could be caused by a neighbour. The only cause is to try and locate the area where the noise is worse, lift floorboards and deal with the problem there.
The squeal when the loo fills is due to a fill valve being past its best...have a Torbeck type fitted and enjoy an almost silent fill.

John
October 2009