Fire door hinge (fire doors are very heavy)
I recommend lift-off hinges if available, because heavy doors are so difficult to take off and replace e.g. for decorating.
Otherwise see if you can get ball-bearing hinges which are a delight with heavy doors.
I could have sworn I'd seen them on IronmongeryDirect, but they have a small range of 125mm, none suitable. I have some of their PVD hinges which are excellent, I might see if they are marked with a brand later.
I checked, and Eclipse do offer them in 127mm, but not much variety. It might be special order.
e.g.
http://www.frisco.co.uk/Eclipse_Hinges/steel_bb.html
I don't know how long Eclipse have been part of Frisco. The range looks smaller, I see fewer lift-off and rising butts than I expected.
I have also come across a company called Essex Hinges who do specials.
Otherwise, two pair of 100mm hinges should do, as used on 60min doors.
Fire hinges are normally rated for 80kg doors. How much is yours?