@Remsey as far as I know you cannot connect a TP-Link Deco system directly to a UK Sky full fibre service as the router does not support Sky's authentication system. Ireland is different.
For reference Sky requires support for DHCPv4 Option 61 with a string in thecform anything@skydsl|anything which always works or DHCPv6 PD which works on most but not all exchanges.
You can however use any Deco system set up,in Access Point mode behind a Sky hub or in a Double NAT set up if you prefer.
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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
