I got in and it didn't break!  I've made a couple of locking bars out of 12mm steel rod that are doing a cracking job of preventing it from collapsing.  These fit into two brackets that I've tacked to the plates on each frame.  This does, however, mean that all there is between me and a trip to the hospital is a couple of tack welds!  But that's fine, as I have complete faith in my welding skills (cough).  I spent the lesson today doing a series of photos of the cockpit at the maximum angle in each direction, and measuring the distances between the ram mounting plates.  This will (hopefully!) allow me work out what the max extension of the rams needs to be, so I can think about actually getting some.  Either way, I'm pretty excited to have been in it without it falling apart!

Finally, I've managed to put it all together!  Bolting the cockpit onto the frame was a bit of a challenge (read painful!), but attaching it to the base was surprisingly simple.  Seeing as the hydraulics are conspicuous by their absence, I'm going to build a simple locking frame that will ensure it doesn't move when I get in.  Next on the agenda is testing, which is going to involve looking at angles and forces.  I can hardly wait...  :P