If you want a ITX motherboard then go for the
ASUS ROG STRIX B450-I GAMING £158.99, Same board as x470-i just a different number & cheaper.
Comes with CPU fan header & also 2 x Case fan headers, True 6 + 2 Phase also,
You will need to update the bios to support 3000 series
https://www.asus.com/Motherboards/ROG-STRIX-B450-I-GAMING/ don't think the bios is out yet
The Asus X570 ITX version of this board will be almost same with 6 + 2, but maybe cost over £220
Being ITX They not really done anything Special with the board & PCI-E 4.0 will not matter or super phase & VRM Due to the Size.
Or also good boards
Gigabyte B450-I AORUS PRO WIFI (Socket AM4) Mini-ITX Motherboard £115 Bios is out F40
Asrock B450 Gaming-ITX/AC (Socket AM4) DDR4 Mini-ITX Motherboard £119 Bios is out P330
I Have the
ASUS ROG STRIX B450-I GAMING & the
Asrock B450 ITX & Asus Prime x470 full ATX