Grenadier Guards In BAOR

Help Required please, I have just come across my father-in -laws
certificate of service that puts him in the grenadier guards in baor from 1945 to 1952 total service 12yrs 365 days (7yr 313 days with colours)
(4yr 52 days in the reserve)
cause of discharge :-Queens regulations 1955 para 634 (vii).
can anybody help with cause of discharge, many thanks ,Mike

I should imagine that it is "On expiration of his period of colour service"

or possibly "on completion of service in section B RAR" (Regular Army Reserve)

I have both in my discharge book.I can let you have a copy of the page if you wish to compare them.

Thanks Gordon, would like a copy of the relevant page to compare if i may,you can email me at mchl_spalding@yahoo.co.uk.
many thanks ,Mike

Done and dusted