Maplin multitool speed control fault

[CambridgeMart]

I have a Maplin 170W 230V multitool that I bought a few years ago. When using it yesterday, the speed control kept resetting to minimum (8000RPM). This model has a digital speed controller with Up and Down buttons and an LCD that shows the speed setting.
Given that Maplin have gone the way of the Dodo, I can't seek help from them; I have discovered that the same tool was sold as a Batavia Maxxseries Rotary Tool 170W, but trying to track down any information on this version hasn't produced any results.
Has anyone come across this type of fault on a similar tool?