Have had our rescue lurcher for 7 years now (he's about 8). He had terrible separation anxiety at first and has always had a tendency to mark in the house if stressed when left but it seems to have increased recently to a rate of about once a fortnight.
Have 2 young children (born after we got him) whom he tolerates but tries to avoid. Not aggressive in any way but prefers to be left in peace.
I have found that the marking tends to happen if we leave the house in a rush / chaotic way or if the toddler is crying a lot in the night (obviously we try to avoid these things but can't prevent them altogether)
He hates being confined to a small area so this isn't really an option - he has the run of most of downstairs.
I do all the right things in terms of cleaning it up but he tends to have favoured areas to mark on.
Any ideas? It's really getting me down.