Unless you have an import (with mapping for another region preinstalled) then, as illustratedman says, you have the memory available for this and should already have the mapping for those regions on the unit.
Even if your 2720 is imported from outside Europe then you should have enough spare memory to fit mapping, routes and custom POIs, should you need them, for your trip. I have an American market 2720 with North America v7 installed and I still have space left over for more than half of Europe as well as all the routes and POIs I might ever want to load. I could fit the countries, in their entirety, you mention as well as the UK and still have space to spare. You shouldn't need all of the countries you mention, just the map tiles for where you'll be going.
Instead of having all of Europe preloaded as I would if my 2720 were a European model, I have to load mapping as I require it although the chunk of Europe I have on there already is more than sufficient for my needs right now. If I need to go outside the area I do have installed it's just a case of selecting the areas I do want in Mapsource, hook up the GPS and then use the send to device button. This will overwrite my existing European mapping but not touch the preinstalled US mapping (more's the pity).
Smudge
