Go to Carphone Warehouse - they pay loads more. My Pixel XL 32gb was worth £140 at CPW, but only £80 at MM. Took it into store last week, quick 10 minute test, refunded the money to my card which arrived the next day. Easier than CeX let alone MM.
just tried and it seems to work, also works on iPads.
Tried this today and is still working
Received the full amount today (including the extra 10%) (y) 🏻 (y) 🏻
Still works today. Just got me an extra £22! Thanks!