Hello
I have a 2860n running on a BT 80/20 fibre line, but now have more users on wifi than Ethernet, the 2860 in heavy traffic via wifi disconnects the users and you need to reconnect, having the issue for a few months I have now turned off the wifi and using a BT smart hub just as a AP, the wifi is better as its running on 5hz ac , which got me thinking can you buy the wifi ac parts and upgrade the 2860n ? To put everything back into one box

No you can't as there aren't enough aerial sockets.. simpler to buy an AP-902 and then you can position it ideally too.