we too have a poisionous snake native to the uk, it is the adder, noone has been confirmed killed by one of these of over 20 years, you hear them before you see them, i used to see a lot in the counrty where i was born and raised has a child but like you never went near them, i wouldnt keep poisionous snakes myself even though i have been handleing snakes for 10 years 1 mistake with them and your toast, i would rather take my chances with a constrictor.