As a Brit, I find that really startling - outside of a military armoury, you just don't see that many firearms in one place. I think you would struggle to buy a gun safe big enough in the UK!
In Every Englishman's closet.
Keep in mind, You only wield one at a time, so just because you have 20 doesn't make you more threatening. Beware the man with one gun, as he likely know how to use it.