Anyone know anything about how broadband actually works?

well, it's a d-link dir-615, it is sold to be used with ADSL too, so presumably the worst case scenario is you'd need to flash the firmware?

anyway, I looked into ADSL modems and it's not worth splashing the cash on one so will carry on using my bebox.

to my knowledge, Virgin routers only work with virgin cable modems, they have their own proprietary firmwares which you cannot change. So probably worthless to most people.