Taxing a car after purchase

[Dum-Dum]

.... tbh i even got a mate to put it on his trade insurance and ive driven it using the 'drive other cars' priveledge on my other policy... my insurance currently know nothing about me driving a 306.

Which doesn't apply because you own the car.

The driving other cars benefit enables you to drive somebody elses car as long as it is insured elsewhere and you have been given permission by the owner to drive it.

The second you sign and date the V5C, the car becomes yours, so you are driving it uninsured.

I was going to say this too. That said your name being on the V5 doesn't make you the owner it makes you the registered keeper but anyway you need to STOP DRIVING NOW untill you get valid insurance as what you are doing is illegal and if you get stopped you could find yourself with 6 points, a £300 fine and your car being seized.