We live in a block of flats, My upstairs neighbour says that he hears my water pipes boning in the morning when we run water and flush our loo and he his being woken up with our problem, We don't hear any noise at all. Would flushing our pipes help. The neighbour has stopped talking to us and the last contact we got was a letter from him. Would like any advice because we all have to live in the block.

Let your neighbor read my response.
To localize this problem both flats have to work together. I have to have your neighbors input. First of all we have to determine exactly where the problem is. Is it in the water pipes or in the drainage? Is the noise worse as the toilet tank's filling or when the toilet's flushed?
How old is your building and what material are the pipes? Did this just happen or has it been going on for a long time? Describe the noise. Cracking or tapping? Loud boom? Sound of rushing water? What?
Answer me and I'll answer you. Regards, Tom