You shouldn't need a lock barrel.
Providing your handle isn't damaged you can de lock it. It involves taking the lock barrel ou and replacing with a dummy. Behind this there is also an
extremely important metal disc which needs to be inserted to prevent it happening again. The cap's just cover all this which can be painted.
It is a very poor design flaw which cn only be fixed by the above method. The de lock kits can be bought from ebay for about £14 IIRC.
Did it to mine before something happened, and was amazed at how poor the design was. You can effectively disarm the alarm, open the door and wind the windows down with a screwdriver...

Won't go into detail on a public forum as it could get into the wrong hands!
P.S if the battery goes flat you can enter through the rear hatch (pardon the expression) via the key and lock, nothing to worry about with that lock , nice and secure!
Sam