So I realised that they were weeing in the two far corners of the pen, as well as the litter tray in the cage. I think Sergeant is going in the litter tray actually and it was just Pepper weeing on the floor of the pen. Great, I thought, I just need to put litter trays in those corners! Which is what I did this evening. First of all they both thought they were new dining tables, due to the hay on top (they barely ever even touch meadow hay normally either!). Then, they decided one was a dig box and a load of the litter ended up on the floor beside it. They then lost interest for a while, or rather, got distracted by the newly restocked timothy hay rack back in the cage. And then Pepper went and sat right in front of the new trays and had a wee. ARGH!