Need advice on my cat

I have a beauriful grey/silver cat she is my world don't know what I would do without her but I've had a lot of people tell me she looks like a Russian blue even asked if she is according to the vets she just a normal British short hair cat nothing special (she speacial to me regardless) but was wondering if anyone knows if she a normal British or if she is a Russian blue looked on google and she looks like one. The reason I asked is there have been a spout of catnappers around my area people marking houses with cats ready to steal if they take her it will be for bait for dog fighting breadung (which they can't do as she been spayed) or sell on and If they think she Russian blue they will make money on her she is mine and mine only!!! Please help I want to protect her as much as I can to the point where she not going out as much as I'm not having anyone take my baby here is her pic hope someone can shed some light on this it won't change how I feel about her at all like I said she is speacial no matter what