Hi,
From the screen shots, it is noticed that groovy script is setting a property at test case level which good, but this is in last step of the test case. What does not make sense to me is that trying access the value in first step of the test case. I thought you are using the steps sequencially. Is it possible to move groovy script to top? Or may be you are running manually groovy step first and then create step separately.
You may try replace(for Vehicle serial number) with the following value in your request :
${#TestCase#VNumber}
