@Matt169 may or may not be an issue depends on the siize of the file, the speed of your connection and how you have networked the xbox. If you post your Sky hub's stats assuming you have a black Skybhub then forum members should be able to see what is going on. See Find your Sky Broadband router statistics
As a guide a recent Call of Duty download was 78GB at 40Mb/s would take roughly 4 hours to come down so 12 hours implies a speed of around 13Mb/s which if you are using wifi is not that unusual.
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65inch Sky Glass, 3 Sky Streaming Pucks, Sky Ultrafast + and Sky SR213(white Wifi Max hub) main Wifi from 3 TP-Link Deco M4 units in access point mode
