Sorry for being thick but renumbered from what?
Your JAR licence is now an EASA licence. When you get to the 5 year reissue point, or have any licensing action carried out by the CAA, it will be reissued as a EASA licence with a slightly different number. This has resulted in pilots with FAA Restriucted Certificates having to have them changed. In your case you do not have a Restricted Certificate yet, but if you are going to get one, it would make sense to do so on the basis of a new EASA number rather that the existing JAA number! In either case you need the CAA to verify your licence so that the FAA can process your application at a FISDO in the USA. I should have referred you to form
SRG 1160 not 2110. Either way, its raised the renumbering issue which could mean you have to repeat the process in the near future if you don't obtain an EASA licence before you make the application.