Our puppy is 18 weeks old and toilet training has been good with him, but the only problem is that if he does need to go in the night he will just go on the kitchen floor.  I do leave paper by the garden door but he only would pee on that. 

This is perfectly normal and I certainly wouldn't expect any different until he is maybe 6 months old, unless you get up in the night to let him out.

It is actually likely that he wakes early in the morning needing to go, and either doesn't know how to call you or you don't here him, and like all babies when they need to go they need to go NOW!!

Thank you for your reply.  I know in a couple of months this will pass, but I do get up with him at 5am to let him out and the last time at night he goes to toilet is about 11pm.  It is just so nice when you get up and you have a clean floor, as he doesn't use the paper I leave for him.

Would not worry guest, within a few weeks he will be able to manage all night without having to empty his bowels. It is no more effort to pick it up of the kitchen floor than it is from the garden, so just hang on a bit and you wont have a problem. IMO it is not worth putting effort into trying to train him not to do it when you can spend that time training something of long lasting use.

I am not bothered by picking up or cleaning up after him its just that he goes out at 11ish for his last wee and then I am up at 5am to let him out.  Often his last feed is around 6pm and he usually goes a couple of hours after that, then also during the night.  I am just amazed that he seems to go so much!

Weight for weight pups eat far more than an adult and so produce far more waste, some foods produce more than others, you should see what they produce when they are first weaned.