Yeah i bought a spare case too as the ONLY key i got with my car was tatty so swapped over all the internals ,i recommended my above post as he only has 1 key and a spare comes in handy
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I would recommend both new case for replacement and new fob and coding, fob off ebay £26, key cutting £8, VW coding £60, total £94 or you can take your V5 to VW and wait 3 weeks for your spare key to be cut and then spend an hour with VW and pay £169.50,I know which im doing
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Same guy does replacement cases for £10, swap out your old internals so £104 and you have 2 new looking fully coded keys (and more inportantly a SPARE!).