we have a king charles puppy which is 12 weeks old, he was doing great going out in the garden to do his toilet but over the last couple of days he's been weeing in his bed, i've been told that this could be him marking his teritory. any ideas?

If you do a search for 'toilet training' there is loads of useful advice on this forum.  We had a CKC for nearly fourteen years - fantastic breed of dog.