The two map overlays mentioned above can be found here: http://www.ukgeocachers.co.uk/garminoverlays/index.php
There are two different versions, one with and one without contour lines. They are easy to install and the webpage has a list of GPSr that they have been tested on and work - so far. if anyone else uses them on another GPSr then please get in touch and I will update the list.
The plan at present ius to get the maps recompilled twice a month and I will post the latest maps on the page shown above.
It is very much a work in process and the beauty of the http://www.openstreetmap.org/ system is that anyone can edit/correct/adjust the maps on there. it is a global cummunity creating their own free to use maps. There are a number of pre-compiled maps on the openstreetmap website for other european countries if you are visiting abraod and don't want to but Garmin Topo maps.
I hope everyoen finds the masp usefull, they look great on my Colorado.
"I Cache, therefore I am"