Knowing and proving beyond doubt are usually two very different things sadly. Ive seen first hand how overstretched the police really are (Love them or hate them it really isn't an easy job) and sadly have to prioritise. Fill out a few forms, get a job number and let the insurance pay out so every decent person can share the cost is the usual approach.
I do worry sometimes how i'd react if I did catch some scrot trying to steal my pride and joy....it wouldn't be pretty but it would certainly be self defence.
Anyway back on topic, good luck with catching the scum, sorry for the rant.