I have a total of 760Dh but only want to sell 500. You can't buy Dirham outside the country so the advantage of having some with you is skipping queues at the airport currency exchange and getting straight to the taxi-rank. This always saves me a load of time, and I then get extra currency in town from the cash machines using my Nationwide debit card (no charges for overseas withdrawals and best excahnge rate).
500 Moroccan Dirham = £35 delivered using 1st class recorded delivery. Payment by Paypal (I'm verified with 300+ pos feedback on eBay). Picture of cash to come shortly if any interest.