Is this restriction on your licence or in your ANO?
Without wishing to be rude DP, that is a meaningless question and the analysis that follows it is flawed.
When the UK CAA grants you a JAA PPL, it grants you a document, the privileges of which are defined within the UK ANO.
The restrictions are associatd with the licence, and the ANO defines what they are. When you fly outside the UK, the UK ANO continues to apply to you and your licence. This is called the Extraterritorial effect, and is defined explicitly in Article 123 of the order.
Once you fly abroad, not only do those restrictions apply, but so do the rules and restrictions relating to the country you find yourself in. Where the two regulations conflict, the more restrictive applies to you, ensuring that at all times, you fly within the limits of your licence. For example in France, the law says that to file IFR, you must hold an IR regardless of the weather conditions. This is not the case in the UK, but you must now respect that restriction too.
If a Frenchman comes to the UK, the chances are that he too will hold a JAA PPL - but this one will presumably have been issued in France. French Air Law places no "in sight of surface" restriction on the PPL holder. It simply says that he must comply with VFR. In the UK VFR permits flight out of sight of the surface, so the Frenchman with his French-issued JAA PPL can fly out of sight of the surface in the UK.
Two apparently identical licences, that contain different smallprint that applies to their holders, wherever they fly.
I hope this helps. It is a tough subject area.