https://www.solenttools.co.uk/belt-performance-power-500w-planer-pp500pp.html see link above... it doesn't have a model number... Probably too late for the op but someone else may find it helpful if looking up the "serial number" in future, which isn't a serial number after all even though it is labelled as such!
That's nice. My car has a serial number 1325476847ww654
487. Unfortuately that doesnt tell you what make it is. Why not do an online search using a well-known search engine beginnning with G but which I am not allowed to mention here, and look for "MAKE tool spares", with your planers make instead of "MAKE"
We may have found other answers which could help you.