"Rotozip" tool (West Hendon NW9)

Rotozip tool , Its a spiral saw, its old and a bit dirty, partly disassembled but easy to put back together, there are a few blades but mostly rusty or blunt, there are some router bits which are new. it can be turned into a router or an angle grinder. motor runs ok, but switch is stuck ON so it spins when it gets power. its like this https://www.rotozip.com/us/en. parts can be bought from amazon. preference given to polite person in genuine need.