The same R/T as an airfield inside controlled airspace, unless radar is not available in which case they may indicate that it is a Procedural Service.
Therefore if they wish you to enter the hold it would be something like:-
"G-CD, Procedural Service, Cleared to the CAM at 3,00ft report entering the hold".
If they are vectoring you to the ILS then it would be something like:-
"G-CD, Traffic Service, radar vectors for the ILS runway 23, fly heading xxx".