Two routers or One or AP or ..

[#1]

Trying to decide what the best setup is?
We have 5 wired PCs, 4 phones, 3 tablets, sky box, harmony hub, Vera home control, networked printer and a couple of Nas boxes.
I've just got a hub one and it upped the speed.
I have it setup withe the hub one on the 192.168 range with a drayteck router. Acting as dhcp server on a 10 range and a wireless router for downstairs and a billion router being an access point for upstairs.

Should I collapse everything to one network range.
If I change the hub one to using the 10 range will that be a problem?
Do I need 2 routers downstairs - one acting as a modem the other being an access point? (It comes from history when I found routers dealing with ADSL and wireless too much and would need rebooting regularly)

Martyn
Over complicating things as normal!

[#2]

what you on about?

[#3]

As far as I am aware, the Hub One won't permit you to use 10.x.x.x subnet, but you can choose a different range such as 172.16.x.x, or say for example 192.168.100.x

https://community.plus.net/t5/Fibre-Broadband/New-Hub-One-wont-accept-10-x-x-x-RFC1918-Gateway-or-DH...

fwiw, if you prefer to keep separate boxes for modem and wireless downstairs for good reasons you have already stated, have you considered replacing the Hub One with a proper VDSL 'bridge' modem, such as an Openreach modem?  Only downside is you won't have access to any DSL stats unless you use an 'unlocked' HG612 openreach modem.

Alternatively, keep the Hub One as your main router and reconfigure your Draytek to become an Access Point if you wish to collapse everything onto one subnet, such as the default 192.168.1.x, and to eliminate the double-NAT configuration.