FS108 problem with streaming from this to 4K TV

Our home broadband has a download speed of around 60Mb/s having just upgraded it. From the router (in our main house

bedroom) I have an ethernet feed to the lounge into a switch there and then various feeds into the lounge TV, and a camera etc.

Another feed from the router goes to an external wired camera. Another to a VOIP box. The final two go out into the garden and provision a shed and our garden office. There is at least 20 metres of CAT 6 cable I think from the router to the office. WHen it comes into the office it goes into a Netgear FS108 switch (this is about 15 yrs old) and from that we have wired ethernet feeds to a PC, a camera, a TV, a streaming hifi unit. The PC in this office room shows a download speed of around 60Mb/s. The 4k TV wired to the same switch is the issue. It simply refuses to stream properly at 4k. It is a new LG OLED that is a year old. 

I just dont understand why there is a problem when I get the speed I do at the PC which feeds from the same switch.

Is there any obvious issue anyone can identify or anything I can try to diagnose the issue?

Is there any issue with where I plug in the main broadband feed from the house into the switch? There are 8 sockets - can I use any of these?

What is the relevance of the Normal/Uplink button?

This switch was originally used with a server to allow connection to a PC but I have since repurposed it. Do I need another kind of switch?

Might it only be feeding at 10 rather than 100Mb/s for some reason?

thanks