DVLA are deliberately very misleading on this and it is unfair. Even DVLA staff will differ in opinion, but you have to remember many of these are agency staff with little experience. The higher up you go, the more experienced people you talk to. They will lead you to believe that the licence is invalid if the photo is not updated and you cannot drive. This is actually untrue, the licence remains valid, but your photocard has expired. You are covered whilst they update it also. I had this confirmed when I sent my own licence back to have the photo updated - and they 'lost' my driving record! They told me to apply for a new provisional licence and take my test again after 40 years of driving!