Samsung is currently rolling out an update to on Galaxy S8 and S8+ in UK. The main highlight of the update is Bluetooth fix. Several users reported that there phone is rebooting when, try to play music via Bluetooth. The same update has rolled out in UAE some time ago.
The update is rolling out as OTA, it will reach you very soon. If the update notification doesn’t reach you than you can check it manually by going through the settings of your phone>>about phone >>software update.
As this is a large update, We recommends you that use a Wifi network for downloading the update. Before start installing the update you should charge your phone at least up to 50%. People who get the update can share there experiences after the update. Whether the Bluetooth bug is fixed or not via comments below.