Vince, I can highly recommend those ear defenders, I have the exact same ones.
This will be my third Le Mans with mine. I've owned two sets of radio ear defenders prior to these (my first set was purchased in around 2005 or 2006) and tried others over the years belonging to friends as well. These are, without doubt, the best I've tried. Radio volume is good, they are comfortable, and they cope brilliantly with those parts of the circuit where we know radio reception can be a bit dodgy (close to the electricity pylons at Mulsanne, for example). And last year, Ayse also bought himself a pair of these, (I believe) he too is extremely happy with them.
I know they're not the cheapest, but In my opinion, you can buy these with complete confidence mate!