Ranch house cages link. They only seem to have smaller shelves at the moment, but if you message them they'd probably make you a 25cm by 19" one. It wasn't that expensive - maybe £10?
https://www.ebay.co.uk/sch/i.html?_d...c=1&_nkw=shelf
Access to shelves is a real pain. I am not happy with most ladders and they can fall down (had that before and that can lead to injuries).
So for most of our hamsters I used to use a large cork log tunnel instead of a ladder - and have it pushed part way under the shelf. So it makes a tunnel to run through, leading under the shelf, and also a ramp to climb up the side of.
I get the Rodipet large size ones as they're not too long like other makes.
Rodipet® Cork Tunnel size L – ca 25 cm long and 12-15 cm in Diameter
If you look on the photo below (different cage though) you can see the cork log sticking out from under the green shelf on the right. It worked really well instead of a ladder.
Attachment 52768