I have successfully forced ants to move their nest by planting mint next to it. However, be aware that mint can be quite invasive unless precautions like planting within a pot in the gorund are taken.
Fantastic! thats just the answer I needed!
I'm plant shoping this weekend so I'll pick up some planters too, the peas are on the back edge of my plot with a sleeper used for banking in the soil so I'll stick a couple on the top there. I was trying to work out where I could pop some mint anyway, I love just whipping out and nipping off some leaves to make tea with.
Was there any variety in particular you used... I quite like peppermint and spearmint...