Sorry to hear about the ongoing issues ellisb51. I've taken a closer look into this today, and can see there may be an issue with the downstream power levels - at the moment they are considered within spec, but with natural fluctuations which can be expected that may be causing the problems you've been experiencing.
I can arrange for a follow-up visit with a senior technician who will take extra time to check everything over - please get back to me via PM and we'll be able to get that arranged for you.
Update: Engineer fitted a test hub alongside (split) with normal hub and advised to only connect one device to his test hub to check if anything internally was causing the drops.
My question is: on the original hub: there are still 1000's of POST RS ERRORS on every channel downstream and lots of T3 timeouts - can this be caused by internal devices?- e.g. if a games console downloading a large file - or are these external factors only relying on VM network?
Even on the test hub there are T3 timeouts occurring on each upstream channel - and only one device (my iPhone) is connected to this.