Phoned Customer Service twice, as advised by Virgin.
It took an hour for them to come back with their solution because they say they don't do this process often.
I was then told to dial 1470 and follow instructions to permanently withhold number, I would then need to dial 141 to release the number for important contacts. Wrote this down as told and informed the agent this was the opposite of the website advice.
Was told to ignore the website and everything would work, it doesn't.
Clearly no-one at the customer service knows how to do this can anyone else help?
Please!
Some customer service training on this would also help others in the future.