LASORS gives some information about what instruction can be given by a FI with with an oml.
Have a look at page 76 and 77 of this...
http://www.caa.co.uk/docs/175/Sectio...20(LASORS).pdf
Which is broadly similar to the entry above mentioned by cab3707 but I think the guidance documents on UK limitations refers to pre-JAR (ie pre 1999) CAA Class 1 medicals, not JAR class 1 medicals.
Edited to correct typos and clarify, (I hope).