Nope,you are deflecting - that X99 mini-ITX motherboard is £270+ so no only your typical melodramatic twisting is in action.
Plus unfortunately for you,the X99 platform is over-engineered for mini-ITX,since sadly for you,Ryzen is an SOC and X99 motherboards need a southbridge so it means more complexity and more PCB space taken up.
Also,any real advantages X99 has in PCI-E lanes,etc is negated on smaller motherboards due to the fact you only have one PCI-E slot and one slot for a PCI-E SSD,etc.
Intel can do nothing about it - an AMD Ryzen 8C/16T CPU at £400 to £500 is half the price of the Core i7 6900K.
The socket 1151 motherboards only go upto 4C/8T.
Plus,sadly for you AMD mini-ITX motherboards will be priced more in line with consumer socket 1151 ones and maybe even cheaper as there is less need for extra chips on board due to the SOC nature of Ryzen.
So going by previous AMD mini-ITX motherboards,probably £70 onward.
Oh,also Intel has no current socket 2011 8C/16T CPUs for £300 which are easy to buy and are 65W TDP CPUs.
So your melodramatic E-PEEN argument Intel can compete,isn't really true.
But you are so terrified that AMD might have an advantage for such systems,you are trying your best to limit damage for Intel,which is typical for you.
I suspect you are scared the secondhand price of your socket 2011 CPUs will be go down TBH.
Edit!!
Also even a mod here started questioning your claims.
Have you sent them a picture of that Ryzen CPU you claim you have now??