One problem: You are conflating WiFi speed with internet speed, you can't really do that. Virgin can't reasonably be responsible for the pile of things that can effect WiFi signal, interference from neighbours, houses building materials, bad/damaged client devices, etc are just a few examples. If you are testing speed, you should do so with a computer plugged into the ethernet port on the back of the super hub, anything else and you're testing WiFi, and not internet speed.
A (very quick) look at Virgins WiFi pods seems to indicate that they are just WiFi repeaters, I've never really been a fan of them. They consume the WiFi signal, and amplify it and then spit it back out again. Of course, if the WiFi signal is already bad in an area, repeating a bad signal is still gonna be a bad signal. It's counter-intuitive, but you may get better performance moving the repeaters closer to the virgin hub, away from bad signal areas. Secondly, WiFi is half duplex, that means it can transmit, or receive, but not at the same time, like a radio. However, this automatically means that a WiFi repeater is gonna cut your bandwidth in half, that's just how it is. These devices are designed for typical consumers, and for typical consumers 180mbps is plenty.
So, first thing, check if performance is bad when hooked up via ethernet straight into the Hub4, if it is, then yep, it's virgins fault, go complain. (Or use the realspeed thing the person above me linked, that's fancy.)
I live in what is probably close to worst case for WiFi, a large 6 bedroom house, with concrete floors. My WiFi is almost perfect, so I'll tell you how I achieved it.
1. ISP provided devices are, in my opinion, just not good. They are free for a reason, put it in modem mode and buy something decent. I use a Unifi USG-PRO-4. I'm using the fancy business Hitron modem and it's still quite bad. It drops the internet connection occasionally and just sits there without reconnecting, forever. I complained about this to Virgin and got told "It's like a laptop, you should reboot it as part of your weekly maintenance schedule"... and this is the business side, so I imagine the consumer side is worse.
2. The solution to poor signal is multiple access points. The Unifi planner is really helpful here, I have 4 in my house but am planning on going up to 7. I use unifi 6 lites. Clients automatically hop between access points as I roam around the house.
3. If it can be ethernet, it probably should be ethernet. PCs, TVs, stuff that is stationary, get it off WiFi, WiFi is a finite resource, the less stuff fighting for WiFi, the better.
I'm on Virgins 500mbit package, and I just speedtested 450mbps on my old oneplus 6 phone over WiFi, while being on the other side of a concrete floor to the nearest AP.
