I also have the Leifheit 52000 Bucket Combi Bought This Item Also
The internal dimensions of the bucket on the ground are just 30x18cm (height 24cm) and thus can no longer be the built-in washer rinse well.
I have now instead the Leifheit 55273 buckets EcoPerfect ordered, which is 50cm wide.
For the Leifheit 59110 Professional built-in washer 35 cm of the bucket should be at least 40cm wide (width measured in the dry state 39 cm). Hopefully this info will save a few others a false order!