I've done the opposite and had property back quicker
The UV markings were placed on the chassis, hidden by the bodywork
For rolling stock it is hidden inside under the seat inserts or the underframe
Also, don't apply the UV marking on easily removed parts, like detachable fuel tanks, etc
A label is then placed visible underneath
This is primarily for exhibitions, making it easy to identify my own rolling stock quickly
The thief thought they had done enough by removing this label, but had not checked for the UV mark
I had to identify the model to get it back, which was easily done as I advised exactly where the UV mark should be