Can you help my Tele-Athenar II lens?

I have a whopping great 1200mm f6.8 Tele-Athenar II T2 mount lens with a Nikon F mount adapter. It measures 1m long with a 150mm front element & is 180mm overall diameter. The lens was made in the USA by Century Precision Optics who were acquired by Schneider Optics in 2000.
The problem is, of its 22 aperture blades, a number have become dislodged and rendered the lens inoperative. As you can imagine, I am reluctant to tackle this monstrous beast and have been unable to find a technician willing to have a go.
Bearing in mind that I and my lens live in the UK and shipping to the US would be an unviable expense for a lens which might be beyond economic repair, does anyone have any ideas?
Before you say it, I know, I m clutching at straws…*SIGH* :-(

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