Ozz,
The most important thing about surface controller fishing is presentation. If the fish are large then i recommend mainline of 12lbs, but this is too big to have between the hook and the float. What i suggest is to create a long hair rig (knotless) of around 5- 6 feet in lengthof clear 8 lb line. Cut a small bit of cork and slide a leger stop in the middle, may need a bit of glue. Then slide the controller on (i recommend a 5gm Drennam#n surface carp). Then tie onto a swivel. Make sure the Float is about 4.5 feet away from the hook and 0.5 feet from the swivel so that it slides. Slip a bit of cork over the swivel so it floats. Another important thing is to colour the cork black so tjhe carp don't go for that instead of the hook bait. Finally grease the with vasiline and you're ready. Make sure you watch the bait instead of the float although some carp really hit it hard and pull thje float down as well. The most important thing is to keep on chucking out freebies and watch out for bloody birds! Also remember to constantly grease the line. This method does work and is my favourite method. I recently landed a 20lb 4oz carp in Stanborough lakes, herts with this method. I also recommend you use dog biscuits, Friskies large ovale shaped ones sprinked with chilli powder. Anyway good luck and thanks for the info on la croix du vieux pont campsite.
Danny