Taken from a car dealers website below. Apparently you can leave a deposit but buying and driving a car away from a dealers isn't allowed unless you are a key worker?
Customer Notice: As of 24th March we will be closed to keep inline with the current government guidelines. We can still answer any questions you may have via email at this time as well as take holding deposits for after these measures are lifted. However if you are a key worker and in need of a car feel free to get in touch and i will see if we can accommodate you.