Fitting Fire door to old frame

Hi Ladies / Gents,

I was hoping somebody could advise me how best to get a new fire door to fit in a slightly wonky lining.
The lining is original to my house, and the door needs bringing up to regs.

I have trimmed and hung the door which fits nice and snug with a 3mm gap on both sides. However i didn't notice until too late that the top of the lining is off horizontal, so that the gap goes from 2mm o one end to 8mm at the other.

Trimming the top of the door is not an option because that would destroy the sticker that certifies the door as fd30.

Also shimming the hinges wont work because then the side gap will be too much.

The only thing i can think is to buy a door blank and cut down to size/shape, or install a thin wedge on the face of the lining. Is this legal?

Any advice would be greatly appreciated, I'm in your hands, thankyou.

 

Thanks for the reply chippie. The BCO did check the lining and told me it is suitable, basicaly has to meet thickness and wood density requirements. Id rather not replace it if i don't have to..

Amazing face rug by the way.

 

Thanks, I'll give it a shot.