I would like a dishwasher installed, i have the dishwasher and am prepared to take the kitchen cupboard out myself. Do I just need a water pipe or will i need a seperate drainage pipe?

That is dependant on the position of the dishwasher. If it is next to the existing sink then the waste from the dishwasher can be fed through and a trap with an extra inlet can be fitted to conect the dishwasher. If not then yes a new waste will have to be installed. Hope this helps Dave