Thank you for taking the time to contact us via the forums in regards to VAT receipts, welcome to the community!
Can you confirm if these are for Virgin Media or Virgin Mobile services? If these are for Virgin Mobile you can view them via your monthly bill. If you open it up, just under the amount there should be two options, one for a PDF version and the other for a VAT receipt.
This option isn't currently available for Virgin Media accounts but we can help further if needed, please let us know.