I'm sorry Kate - I understand your pain. I can't tell you how many I lost over the winter to voles. No matter what I try it seems impossible to get rid of them. Lucky for me they seem to leave in the spring and not return until winter. There is one new thing I haven't tried yet that I just purchased and will use this fall.
http://www.plantskydd.com/vole... I'm not sure if you can get that there or not, or if these people ship internationally. I've used their other products on deer and rabbits and it's excellent.
Good luck.
