No, it's not a visiting Great Dane, it's Monty having spent the night on Lady Magnon's sofa.
The poor boy has been having back leg problems recently (early hip dysplasia?), so Lady M has been pampering him even more than usual. Tasty bits of steak from her plate, extra treats when she thinks I'm not looking, and forbidden nights spent on her comfy sofa.
He is, of course, her 'baby', so he's having masses of special attention heaped upon him.
Swimming in the lake every day (it's supposed to be good for him), giant Cod liver oil pills (they're supposed to be good for him), and plenty of time spent snoozing on her sofa (she thinks that's definitely good for him).
Oh, and I forgot to mention; Bok sleeps most nights on MY sofa too! Naughty boy.
Whoever coined the phrase 'rules are meant to be broken' was an idiot (and 100% correct).