Hi. I've just popped down to local PAH in Stockport and they said they don't sell the toppers separately like they used to; you have to buy the whole thing! So like you am looking for a topper but I need a 3ft one!! Don't think I'll find one though. Hope you find one . If find supplier will let you know. Flo.
Amended....However, having just read through several posts on egerbil uk site, there does seem to be a worry that the toppers aren't necessary and its better just to get a bigger tank and put more substrate in so the little furries can dig and burrow like they were born to do and not climb. One worrying feature was that they can start chewing metal bars, which is not the best??