Try a small amount of Vanish carpet cleaner, blob it on, leave around a minute and dab it off with a damp cloth.
I have also heard hairspray is good for getting stains off suede, no idea how true it is though, I would go with the vanish method.
Previous owners pen and most definatly a small child's work, I've not had the car long and it's on my to do list
I did manage a full detail and extra gloss protection yesturday and I'm doing the inside today
This lot cost a little over a fiver I've used the Vanish fabric stain remover first and scrubbed it with the tooth brush and I can't see it at all but will wait until it's dry before going any further or trying the hairspray