Thank you both @Trex and @Aashish.007 .
The issue was two fold:
1. the 5GHz channel width was set to 40 MHz. Changing this to 80 MHz increased the speeds to around 180 Mbps
2. Enabling software flow offloading brought the speeds up to 220 Mbps
The issue was two fold:
1. the 5GHz channel width was set to 40 MHz. Changing this to 80 MHz increased the speeds to around 180 Mbps
2. Enabling software flow offloading brought the speeds up to 220 Mbps