Hopefully they will release a Gaming 4 at some point to plug the gap. I agree though, as someone who was looking in that ~£150 price range there is not much of a choice.
Hopefully, there is a couple ASrock options in that price bracket it seems, a Fatality.... straight up nope from me, and a Killer.... urrggh, depends if that is just a random name for a killer board, or if it has money wasted on a killer nic.
Trying to think who else there is, there is an MSI around the same price bracket as well. I think the thing is, the £150 boards I'm seeing look more like £120 boards and the £200 boards should be a real option at £150-160 and offer decent value if you want to spend the extra. I mentioned before, with the pricing on the CPUs, it seems unlikely that AMD is trying to milk the chipsets, which are more basic being that Zen is a SOC, so more of it is on the CPU and included in the price of the CPU rather than mobo.
The old days of £80-95 for a really decent board then £130 for boards pushing well into top tier, motherboards are frankly getting cheaper. The chipset costs have gone down significantly, the expensive many more traces parallel connections are all but gone which saves a lot of complexity. Brexit should have pushed these up £20, not £60 imo. I think this is mobo makers having had a good run with Intel and just matching up prices rather than passing on the savings of cheaper chipsets and boards from AMD.
Another factor is X99, this literally costs quite a bit more, more pci-e lanes, quad channel memory, more I/O. I got a MSI X99 something or other board for £170, that was at a time where X99 significantly outpriced the mainstream in general.