I managed to find the specification of a Kemitron K3000E, in a PhD Thesis from Loughborough University, where a K3000 was in use in 1986.

Processor:  Z80A, 4MHz.

RAM: 64K RAM.

Storage: Dual 8” DS/DD Floppy Disk Drives.

Interfaces: Expansion slots for I/O cards.

OS: CP/M 2.2.

The Kemitron 3000 series appears to have used the same processor as my Kemitron MZB-3 CPU card, but the form factor is unknown. Dual 8" Drives would require a large(ish) case though.

Some further detail is provided in the September 1979 issue of "Practical Computing" which has an article focussed on Kemitron Electronics. The article describes the Kemitron UBS 3000 as having a modular construction with the option to plug any of a number of cards (Processor, RAM, CPU, etc.) into the system bus. The article also suggests a variety of processors might be available.