Sorry if I'm stating the obvious but there's more to silver the just DXB lounge access. I recently helped a friend with bookings and airport check-in at LHR for a trip to HKG. He had to pay for advance seat selection x4 for the four sectors he's flying, plus the check-in at LHR took nearly an hour. I get none of that nonsense as silver. It would be worth it to me to pay the £300 if I had no other option.