Wireless signal drops when uploading on new inspiron 13-7000

I got this new laptop 12 days ago and it has had issues with wifi connection problems since day 1. Connection is lost as soon as I attach a photo to an email, upload files to the cloud, etc. I can reliably 'crash' the connection by doing the google M-labs speed test over and over again - usually crashes after 2-3 times.

I have contacted dell support who wanted me to send the laptop back for up to 14 days to be repaired. This is not acceptable as I have next day onsite warranty and this is a brand new computer which is faulty from factory.

I've been trying a bunch of things to try to figure out whats going on.

• I've updated windows 10 from build 1703 to 1709 which is supposed to fix some networking problems. 
• I've updated the firmware on my wifi router (Netcomm NB16WV-02)
• I've tried drivers for the Intel AC 7265 wireless adaptor from Dell, windows and Intel
• I've updated the BIOS and chipset drivers.
• I've tried the same speed test on 4 different wifi routers with the same failures every time
• I've been able to avoid the problem by pairing the laptop to my iPhone hotspot via both bluetooth and wifi
• I've tried with bluetooth turned on and off
• I've had a dell support technician take over my laptop remotely and apply a range of settings on the advanced tab of my wireless adaptor
• I've done a full factory reset on the laptop
• I've run several diagnostic tests through windows, dell and intel and they all have come back 'normal'
• every other device on my home wifi is performing as normal with no issues
• I'm now trying to arrange a time out of my busy schedule to meet with a warranty service technician at my home which is proving difficult. I could have them meet me at work, but the problem is with my home network.

It doesn't appear to be a hardware problem, but I've tried so many configuration changes with no success.

I'm wondering if anyone else has had this problem?