This configuration was working as-is with a 2820. I swapped out the 2820 for the 2925, and I'm sure it was fine for a few days. No loops, etc that I am aware off, and certainly the switch isn't lit up like a Christmas tree.
I then obtained a DrayTek router tray, so on Friday I mounted the router on that and pop it into my rack at home (it is in the loft, and nice and cool - so much rain currently). It has been Friday onwards since I notice the reboots.
As the device was now plugged into a power surge protected PDU, I initially disconnected that and it is running direct from a UPS (as how the 2820 used to be). Had no affect in its rebooting (changed that on Saturday AM).
When I rack mounted the unit, I used some wifi extension cables, and mounted the aerials (just the 2 of them as this is only the n unit) externally of the rack. Having googled, I found an article were someone had a 2830 (iirc) and that unit was rebooting a few times a day; and they (seemingly) cured it by disabling the wifi, so I'm currently giving that a whirl (using an AP-700). Can you guess that I am a DrayTek fan?
Next step, I'll flash it again with the RST and go as basic as I can - change of LAN IP range, DHCP option 61 & MAC for Sky Fibre, and leave wifi off. As basic as it can get.
If it still continues I'll unrack mount it and run it on a shelf (how it was till before Friday).
Unfortunately I bought the unit from ebay (it was brand new, and still in its original seal bag in the box. Guess I could try returning it to the seller as faulty if DrayTek support won't help me.
Link to rack image
Speed test result
(when it isn't rebooting!!)
Edited by mbames (Sun 23-Aug-15 13:18:33)