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'm 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*

You don't say where you are, but there are many camera and lens repair shops in London. Contact them, one of them will give you the correct story. Don't believe the first guy if he tells you it can't be fixed. I had a job where I sent a machine to a factory in Billingham, spent a few months there, so I know not everyone is in London.

I would attempt to fix it myself, if no one will fix it for a reasonable price. Just get a proper precision screwdriver set, work slowly, mark the assemblies with a marker pen so they can be reassembled in the same alignment with one another. Take pictures during the process.

You might get a few broken camera lenses to take apart first, just simple ones. The iris is usually between lens assemblies.