Same here for me. Persistent little twerps aren't they!! As you've found, Virgin are at least sending "most" of them directly to the Spam folder. Regarding getting them blocked at source, you could try the following suggestion (unless you're already doing so?) : -
You could try forwarding the rubbish from the scummers to the free service by phishing.gov.uk via firstname.lastname@example.org and hopefully get them blocked at source. I've been doing this and it certainly seems to have worked for a number of other scummers.
More information about the service here ...
Rather than simply forwarding the spam-crud directly (you could try though) as this might get blocked by Virgin's filters 🤔🤨 !!! ... I tend to "Save-as" a *.eml file and forward the saved file(s) (as a batch) to the email I gave above. No need to subscribe and it's automated - sending you a brief email of confirmation as soon as they receive your files (so no need to write anything in the email you send).