From THIS THREAD over in GD.
They have quite a nice setup in the old MI6 facility. LINK with plenty of photos.

I wanted to go there when I was there six years ago but my (now-ex) wife vetoed it.  Maybe next year.  I’ve read a few books about all of that, very cool stuff.

How about this one? LINK

Yup, just last winter.  I think I still have an unread one on my iPad as well.

Of all the setups they radio club has in that building, this is the one I'd like to operate.

On the left is a BC-221 signal generator used either as a VFO to drive what appears to be a repackaging of one of their spy transmitters or to verify the transmitter frequency. The receiver is a late '30s/early '40s National HRO.
The HRO was a favorite of MI6. With their first order, MI6 told National, "start making them, we'll tell you when to stop".