Hi I have BT fibre with 3 black discs and require robust Wi-Fi in a detached garage which is converted to a family games room etc.
I think the only robust option is to run a network cable from the router is which on the front side of the house all the way around to the garage and connect to an access point.
In the garage I need a hard wired connection to tv decoder box and also Wi-Fi signal for general usage.. any recommendations on access points and switches etc?
The Ethernet option is by far the best way to get Internet in your garage.
Depending on whether you want dual band wifi or not, TP-Link do numerous Wireless Access Points starting in price at about £20 upwards.
You would just connect your Ethernet cable to the Ethernet Switch then use one of the switches sockets to connect to the Wireless Access Point.
The other option is you could consider using Powerline Adaptors if your garage is connected to the same consumer unit (fuse box). You can get ones that are a wireless access point and an Ethernet connection.
While not as good as Ethernet they would save you having to run a cable to the garage.
If you're unable to run an ethernet cable between the main property and the detached garage and the power supply runs off a different consumer unit then another option is to look at creating a Point 2 point wireless bridge between the two buildings. This will need to be line of sight and maybe overkill (P2P networks are usually for connecting 2 places together that are over several kilometres apart)