why would you want too ?
The FRTOL is a Flight Crew Licence ANO Sched 8
Personal flying log book
35 (1) Every member of the flight crew of an aircraft registered in the United Kingdom and every person who engages in flying for the purpose of qualifying for the grant or renewal of a licence under this Order shall keep a personal flying log book in which the following particulars shall be recorded:
(c) the capacity in which the holder acted in flight;
(2) Particulars of each flight during which the holder of the log book acted either as a member of the flight crew of an aircraft or for the purpose of qualifying for the grant or renewal of a licence under this Order, as the case may be, shall be recorded in the log book at the end of each flight or as soon thereafter as is reasonably practicable,including:
So if this was the only licence you hold and you wish to renew it you have to comply with Article 35.
Operating Capacity is logged as RTO!