If you're a motor trader, you can drive a SORN'd vehicle on trade plates if: it’s only temporarily in your possession (until you sell it), it’s being kept at your business premises, the registered keeper has notified DVLA that the vehicle has been sold or transferred to you. More details here: www.gov.uk/sorn-statutory-off-road-notification/mo...s

If you have further questions, you'll need to speak to DVLA. There might be some grey area as you don't say whether you've notified the DVLA already that the car is in your ownership.