Maps on Etrex Vista Cx

Hi

I would like to know if it is possible to view Memory Map maps on the
above device. I am talking about Great Britain OS 1:25000 maps as
they seem to have more detail compared to the base map.

regards

No, but you can plan your waypoints (known as marks in Memory Map) and
routes in Memory Map on a PC and transfer them to the Etrex and later
transfer your tracks from the Etrex and view your them in Memory Map. The
Etrex and other Garmin basemaps have very limited detail, perhaps more like
that of the Memory Map route planner. If you want detailed mapping in the
Etrex Vista Cx you need Garmin (or compatible) mapping. If you want
topographic mapping look at their Topo Great Britain.