or does it have to be for primo 2 only

The dem works in iGO8 through to Primo 2

And probably through to Primo 3.0 or 4.0.
Have not really seen a 'new' DEM file since about 2008-2009. Which in GPS terms, is just short of since forever.

Just a quick question, I already have Terrain_Europe_NASA.dem which is some 263Mb, I noticed that in the download there is a UK specific dem file as well as the Western Europe one. Would it be better to use all three files or a combination assuming that my system can cope, it has so far. I assume that just by adding the UK specific file to what I already have would be the best combination, but to quote YT 'I could be wrong' Thanks

I doubt there would be any difference between the UK part of the Europe file and the UK only dem file, it's not as if the landscape changes much here, if you see terrain detail in the UK with the Europe file then I would just use that.

Just my 2cts here. When you or your GPS never leaves the UK, why not use the UK-DEM only? Or the W-Europe when you do but not leave Europe? The smaller the file, the better the performance of the device should be since more free memory should be available. No need to stuff the memory up with unneeded things.

I do go on an occasional 'booze cruise' to France, in fact, just last Saturday. I'll stick to my original .dem file as advised as there is no lack of performance on my setup. Thanks again guys.