I'm out of contract and due to repeated outages, terrible customer service (the wait times have always been terrible!) and speeds no where near what I pay for I've decided to downgrade at the minimum (and maybe cancel).
There's nowhere obvious to downgrade on the Virgin site (surprise surprise), can I do this online or do I have to sit in a queue for an hour, then get passed between departments for 30 mins?
No online way of downgrading or tailoring packages (VM can't allow customers to do that!). You can use the VM text service request to ask them to contact you, I can't speak for how quick or effective that will be, and on the basis of long experience of the company I don't hold out too much hope. Or, you can be on the phone in a queue for hours as per normal with Virgin Media.
I think you should consider what you want. If you have (or soon will have) Openreach FTTP as an option, then you could get speeds up to gigabit from other suppliers. If you only have FTTC, then you'll be looking at connections in the range 35-80 Mbps. That's still quite useable for most households, and you'd expect better latency performance than VM can offer.
If there's ANY prospect of you cancelling, you need to consider your alternative options BEFORE calling VM, do your research so you know what competitors are offering. If you just want phone and internet, consider smaller ISPs like Zen Internet, uno, IDNet, Aquiss, as they offer far better service and support than any major ISP. If you want TV packages as well your options are with companies as large and grim as VM. And if you do leave, then get the new ISP connected and working well for a week BEFORE you cancel. Because of your one months notice required by VM, that'll mean you're paying for two ISPs for five weeks, but If you don't do that there's a risk, particularly at the moment, that your new installation gets delayed or is faulty, and you're without connection for an indeterminate time.