Hey SonnyD,
There comes a time when you have to 'TELL' Virgin Media to send a technician round to solve your issues ... Not to just pop round, do some basic checks, then say they will be back.
With all due respect, you are purchasing a service from Virgin, in your opinion, that service is clearly woefully inadequate and unfit for purpose. Therefore they have an obligation to fix the problem and supply the best service, and if that isn't happening then they need to put some REAL effort into fixing the issue.
If you bought a brand new car but it was missing the drivers' side door and the bloke in the showroom said it would be delivered next week, you wouldn't drive off the forecourt. The same applies to Virgin, it's THEIR obligation, not yours.
Steve
Utrinque Paratus