If the UK is not totally different from the rest of the world in this resepect, then yes, you can. You don't hold a taxi driver's license either, yet you probably drive yourself when doing business trips by car, or not? Even when there are other people on board. It no different from that.
It only changes when the focus of your employment shifts to flying other employess around without you having any business to attend at the destination. (Which is what I am doing.)