UK Dial Tone In France

I see there are companies who will allow you to have a phone line with a UK number and dial tone while in France. Does anybody use a service like this and if so any thoughts on how well it works for you? There seem to be a few around but here is one example: http://www.ttnc.co.uk/call-management/bolt-ons/uk-ringtone/


The point of something like this is for people running businesses who don't want their clients to know where they're based - sneaky!