Not sure why I picked this as my first newbie job, but after several hours spannering hammering and swearing, I managed to get to one of the trunnions.
Packed solid with black grease, which might explain the stiffness. Cleaned it out, inspected the vertical link (looks good), and shoved it all back with a new grease nipple & big dose of ep90.
Other side will have to wait as I noticed a few things I wasn’t prepared for (mostly bushes), plus looks like the inner hubs need some tlc as I think there’s a rubber or felt seal missing.
Will likely go trunnionless if I rebuild all this properly, but how do you remove / install the stub axle? Seems a solid bugger.