we recenetly bought a neopolitan mastiff, well before christmas.we did the basic house training and now succesfully barks at the door when he needs the toilet. But he will wee on the grass but he wont poo on the grass and just drops it where he feels like it weather its at the gate or outside the back door. can anyone help us to stop him doing this,please.

Unless you take him to the spot you wish him to do his poo in then he will do it where he prefers.  If it is really something you need to do, then take him out every time and don't let him dump in the places he does now, and if he goes where you want praise like crazy.  With rpetition he should start going there.  May be a good idea to take a bit of his offering to that spot as dogs like to go where they have been before.

Try and keep him in the area that you wish him to 'go' , then praise as well as 'treat' when he does...at the same time saying a suitable command word (I actually say "Good Poo" - other people find alternative words :)  )
As long as you are consistant...including the 'treats' for some time...this can actually lead to 'going' on command (for want of a better expression....and I know I certainly can't anyway !)

HTH
Jo
:)

I have a cavalier king charles spaniel who won't go to the loo when it rains!
\any suggestions? He's 9 months old and is fine otherwise.