Yeah but SIM data throughout will never match fibre. I have a 320 Mbps 3bb LAN fibre connection and a 15 Mbps WiFi SIM. There's no way I can run an IPTV box on that.
Re data throttling. Early on in the buffering problem, maybe 3 months ago, the 3bb engineer came out after I suggested 3bb were throttling. He tinkered around for 30 minutes and left saying all clear now. Not sure in relation to what. But thereafter it was the nightly blue circle buffering that occurred, sometimes avoidably, by switching channels (eg UHD to FHD) sometimes persistently. I'd ring 1131 and get them to "reboot the server" (their suggestion) at their end. I've no idea what they actually did (they still do it) but it did sometimes work. I'd also reboot all my devices, box and router, whenever it got really annoying.
Seems like we're stuck with it until there's a fix on the cable, if that's really the source of the problem.