Leaking powder drawer on Hotpoint WD61?

Water is leaking from the bottom of the powder drawer at the beginning of the washing cycle, i.e. when the water flushes the powder into the drum. I have checked that the drawer and pipes into the drum are clear, which they are (stripped the drawer out to check, etc). Water appears to flow into the drum quite freely when doing a 'clothes and powder free' cycle. Checked the 'sump' for any obstructions, such as socks and coins, etc, but that is fine. Water pressure is not set too high. I feel as though I have exhausted all my options. The answer must be simple, but I guess, a closely guarded Hotpoint secret solution, otherwise we could all fix this problem!