Which model Graham? mTech have sold / are selling several different models. Also, more than one company called ‘mTech’, selling stuff other than DRO’s, so they complicate the search. Knowing the model number is important.
Quite likely Clive is right and it’s a relabelled bog-standard DRO, in which case the manual is probably online, if you can identify the model. (Any manufacturer information on the back, or maybe inside?)
Dave