my 4 year old dog keeps weein the kicthen every other day the smell is quite bad i am allways mopping up with bleech but it does not seen to take the smell away

Jeyes Fluid will help to a certain degree, do you have laminate on the floor..if so get rid and replace with tiles(if possible), the wee will have gone down in between the joins. Can you crate him over night and while you are out..this will help a huge amount.
You can buy Jeyes Fluid thats safe to use indoors..Wilkinsons usually has it or Asda etc.
I was always told not to use bleach as the smell of the bleach encourages the dogs to continue weeing in that place. Try something with a citrus scent..it might help.
Good luck..

Water with vinigar in.