I managed to borrow a spare enclosure for a while to keep the smaller snake in but since I separated the two they've both gone crazy! Monty, the larger one, hasn't stopped patrolling her house searching every corner of her cage and rubbing up against the door trying to open it, and the smaller one is searching as well, but a bit less passionately. When I opened the door Monty slid out herself exploring and headed straight for the pillowcase the smaller one arrived in. In the end I had to take her away from the pillowcase and has continued searching all through her enclosure. Monty did do that before we introduced her to the new snake but I though had something to do with the season, but she's gone searching for something again. It's strange but I think they miss each other.
If they don't calm down soon I'll put them back together under close supervision and see what happens.