Servicing ; 'Performance Power Pro' Pruning/Multi-Saw?

The model is CLM18VMS.
The blades are locked into place using an Allen key that controls the side to side movement of the blade.
However, on my tool the housing for the blade is working loose and permits vertical movement.
Unfortunately there does not appear to be any way of gaining access to the two securing screws except, possibly.drilling an access hole above the blade housing.
Has anyone else had this problem (the Power Pro helpline said that there were no arrangements for servicing this tool)?
I think it deplorable that B & Q sell such a tool without servicing being possible.
HELP
Ron 31 Jan