You are quite right however, the GID is not entirely correct. There is nothing in JAR-FCL that says you must have done the aeroplane hours in SEP Class aeroplanes, that is an invention of the UK CAA. All your previous hours will count.
You may find that after a long lay off you will need a minimum of 20 hours to pass the Skill Tests however, if you can do it in less there is nothing to stop you. Rest assured nobody will cut corners if you are notup to it.