Hi Nigel,
Sorry, I searched for threads using similar radio modules to mine, and probably clicked on yours by mistake. The one I use is a radio module DRA818 and not a Wifi module. Anyway, I have answered my question, by tests earlier today.
Cheers, Camerart.
The ones I'm using aren't WiFi either, they are specific data modules (using the 433MHz range) - the DR818 appears to be for making your own 'walkie talkie' type radio, not for data purposes.
Assuming you're wanting simple data transfer, the modules I'm using are absolutely trivial to use - whereas the DR818 looks to be pretty difficult, and may not be legal for data transmissions anyway?.