if you are renewing your license do it online if you can, if you have to pay then apply as if you have lost your license, that way you will have your old license to hand. so long as you respond straight away dvla will have your old license in their system, they destroy them after I think is either 3 or 6 months. so long as you respond within that time you should be safe.
Still got my paper one and have no intention of obtaining the photo card one so that I can be another cash cow for the govt every 10 years (or whatever the renewal interval is). Also, there's no way I'm taking the chance of being at the mercy of the judge and jury known as the DVLA.There was a story some years ago of a biker cop losing his bike entitlement due to a DVLA cock up. They would not admit wrong-doing and would not accept written proof from the chief constable that the cop had been riding and testing police bikes for years. The copper had to retake his tests.The inconvenience for work, the loss of no-claims and I assume being treated as a new rider by the insurance companies if you're unlucky enough to have suffered DVLA incompetence is not worth the risk.
Whenever I need to get a new licence I say the old one is lost (both parts) so they don't need it back. The old one works as my proof of entitlement should they fec up when I suddenly find it.