Roberts are a UK manufacture of portable radios. At the dawn of the transistor era they produced this classic.
They are still UK based and owned by the Glen Simplex group out of Yorkshire. This radio has survived in numerous iterations over about 60 to 70 years now. So the current version has DAB radio, but still looks essentially the same and available in multiple colors.
The OPs recorder is a
rebranded Akai machine with cross-field heads.
Almost certainly this machine will now require the restorers hand. I have never been an enthusiast of Japanese tape machines but many are. I really only know Revox and Brenell mainly, but also to some extent the totally mechanical Ferrograph and Vortexion offerings based on the mechanical Wearite deck, but not the solid state logic decks which were a nightmare.
I think your biggest issue will be parts. I would post on Tape Heads, where there are a lot of aficionados of Japanese reel to reel machines, which I am not. I am definitely Eurocentric when it comes to reel to reel tape machines. I cold not begin to estimate the machines value.