On the flip side having spoken to the poor victim, he managed to get some of his guns back as the numpty that burgled him was a labourer or something who had seen or knew or just guessed from the hard cases what was up and decided to comeback for them. The owner did some digging and managed to point police in the suspects direction and managed to get some stuff back, unfortunately some the guns (including his precious PSG) had been moved on by the suspect and sadly will probably be lost forever.
As to why police don't treat RIFs any differently its because they are treated as such, as property from a burglary.
Most officers in the area have probably been given an intel briefing that replica firearms were stolen but thats probably it.
The crime is being treated as a Burglary because that what it is.
As for the Burglary that happened at a shop, without CCTV, Forensic or witnesses there isn't much to go by.
Whilst CCTV may catch the suspects in action, try and ID someone from grainy moving images and grainy images is often the best you can get, even the best cameras in the world are useless most of the time at night as they switch to black and white.
Forensic wise the scene of crime will only dust for prints at best, they wont take tool marks or shoe prints often as lets be honest one crow bar (or more likely flat head screwdriver) mark is the same as another and most oiks all wear Nike AirMax trainers and gloves especially in this cold weather.
And as for witnesses, probably the most reliable and unreliable source of information sometimes, often neighbours are totally oblivious of whats going on next door or you could have an incident say a stabbing (not uncommon in London) where 50 people saw it, 10 will tell you about it, 5 will give you their name, 2 or 3 will give you a statement, and probably only 1 might turn up to court but only after being begged to come.
End of the day it all boils down to one thing, you may think it absurd but it's "COST", most if not all forces have no money to spend.