Long story cut, I decided to rent out my house two years ago and could not take my two large ant colonys to the new house we were buying. I decided to uncouple the two tanks containing the colonys and partially bury them at the bottom of the garden and open up all the flaps. I got bit many times doing this One contained a mature Myrmecia pyriformis and the other a growing Solenopsis invicta colony. I didn't think they would survive long in the cold Birmingham climate but didn't have the heart to exterminate them. This week the tenants decided to move out so I visited the property to inspect before having viewings. I had a brief chat to my old next door neighbour who complained last year their garden was totally overrun by ants and they believe it caused the death of their cat, Tardis. I panicked a little because I can't remember if I ever told them I kept live ant colonys. I checked the garden found both species flourishing. I'm astonished. How far could they have got to? Is it too late to try and dig them up or should I let them be?