WabbitPoo - yes, hadn't even thought of that and it would be the best solution. Unfortunately (1) with the walls being a bit wonky I'd worry I didn't get lining edges perfect and they might show through, and (2) don't have enough paper and no time to buy more (panic setting in as visitors arrive next week!). But thanks v much for the advice.
Bosswhite - thank you too, good advice.
Bosswhite - thank you too, good advice.