IRS fuel tank removal

[V8falcons]

So I have the dreaded fuel syphon flap dropin(you could call it) in My AU XR falcon..,where i cant fuel my car up any more than about half a litre a minute...
so the tank or filler needs to come out to remove the flap and got under it on the week end ,undid the outside bolt no probs but the innner/upper bolt is almost impossible to remove... anyone got one out will out dropping the IRS? which looks to be the case at a quick glance....