See, when people mention onions I always think of Shrek!

As mentioned the testing was basic, I just did a file transfer test from a device on one switch to another device on a separate switch (each managed switch is directly uplinked to the router). The theory is that the traffic has to pass through the router. I was getting a steady 100Mb/s (1Gpbs) transfer rate.

Fully agree with you over the security, for me I go the "disable all unused ports" method to stop random people plugging into the network.