Gillian, I would totally recommend the wee-wee pads (you can get them in most petstores or on internet if there's none near to you)...

We did this for our two and it worked in 2 DAYS!!!! We only finished our pack of 7 as we had them but after about 3/4 pads, they knew what to do ....

They MAY miss a little in the beginning but you really should see the results very quicky ....

Good luck