Just got my Deco M5 setup (3 of them)

Really enjoyed how fast it was to setup, I'm getting some interesting results:

Ethernet PC
Ping 12ms
D/L: 364Mbs

U/L: 25.10Mbs

Wireless Macbook Pro

Ping: 21ms

D/L: 158mbs
U/L: 20mbs

I'm wirelessly connected to the Master Deco, that is connected via Ethernet to my PC and the Cable Modem... the laptop is about 6 inches away from the Deco... and is connected at 5ghz // 866mbs

I've not got any QOS enabled, and Antivirus is disabled (all via the Deco App)

Where should I start looking/diagnosing to improve that wireless download speed?

Many Thanks!

Adam