I'll go on a limb here.
At first glance, I personally doubt that such an attempt would be successful. It would be a seating duck for air attack or sub attack and there is no guarantee that it could survive the voyage. Such a voyage would be very slow, perfect for a canny U-boat commander. Logically it would have to be heavily escorted, thus diverting needed naval units for more vital missions.
I don't think it would have been worth the effort or risk to bring it to another shipyard for completion.