@Hank21 thank you for your reply. 

I have the SM5310-T 10G BASE-T RJ45 SFP+ modules

There is only one LAN subnet 192.168.10.0/24 all set to VLAN1

So far, I've found that a small 6 port 1GE unmanaged cisco switch will only work when I set the connected port to 1000 Mbps - If I set the port to 10G the devices connected to the cisco switch do not get DHCP even though the NIC lights are green and yellow to indicate 1 Gbps.

I have a minipc with 2.5Gbps NIC and the only way I can get this connection to work is to go into the SX3008F to set the port speed to 1000 Mbps, then disable the port, enable the port then change the port speed to 10G and finally the minipc will get DHCP and work at 2.5 Gbps

I disabled the four ports that are not being used in the switch.

I was hoping that TP-LINK would be reasonable products, but I'm amazed at how badly this is going.

so what is the current status when I boot switch.

Port 0 10Gbps - upstream ok

Port 1 10Gbps - HP Z6 G5 with 10 GE NIC ok

Port 2 1 Gbps - Cisco 6 port unmanaged 1GE switch with printer, etc connected ok

Port 3 10 Gbps - GMKTec minipc with 2.5 GE NIC fail

I have a second SX300F and 8 SFP+ 10G modules still in boxes - I'm worried that if I deploy them my home network will really screw up. I've ordered an OC220, but from what I read this won't fix the hardware failures / firmware problems.

Any guidance appreciated.