It’s an airsoft replica of the Benelli M3 super 90 shotgun, not a Winchester, not even close.
 
I can also tell you that its a Chinese copy of the TM Tri-shot system, one of the best airsoft shotgun systems in existence (and my personal favorite.)
 
I can ALSO tell you that given the colouring, it is probably owned by a non-airsofter who lives in the UK.
 
The reason for this last one is the laws in the UK regarding Imitation Firearms (IF) and Realistic Imitation Firearms (RIF)

Got a few more of these yet

At this rate we’ll have enough ponified small arms to invade Guatemala.