[BenMcr]

virgin will always allow a number port to go through, as long as it is requested correctly

Problems can occur when the exchanges don't match up, as Virgin have different areas to BT, or if the number is being moved at the same time, the original postcode hasn't been provided as part of the port request.

Apart from that, I don't know anything else that would cause a problem.

Was the number issued to you by Virgin or was it a previously ported number?

I've never actually seen a residential to business number port between Virgin and BT, so that might also be a factor