ILS can be almost any GP angle within reason; London City has GP's of 5.5 deg. ICAO won't allow an ILS to be Cat 1 if it's more than 3.5 deg, and Cat 11/111 MUST be 3 deg. I don't have access to charts for LGIR. Is there a non-precision approach to the runway in question? Does it have a 'nominal' gradient (something like 5% = 3 deg) or RoD for this approach? If so that would give you a rough clue as to the likely GP or angle