On motor homes the are usually mounted centrally between the sun visors and are the oscillating variety.On grounds of safety, anything additional on the dashboard is not a very good idea. The car manufacturers go to great lengths to make sure that the dashboard provides adequate energy absorption in the event of a crash and this would be put to waste if a hard object is placed in between, especially if it has any sharp edges.
Lidl should be stocking something that might meet your needs on 11 June, for