I found looking on the net a company called WEBTEC, sure they sell the later design control valve.
I emailed them and they sent me the rubbers covers as mine was well shot, due to the water ingress the lever pins had worn, these I had to make..
I found they are retained by a ball bearing forced in spreading the end and knurled area.
The lever arm are painted and new end caps are from Rs components.
I replaced all the hoses on mine, I'll post there telephone number due to there really reasonable cost.(cheap)
Only pain on mines been the main slew pin, ass to remove (looked like an orange skin) rusted to hell.
took 20 tonne to move mm at a time.
Bearing shells I found to run a hacksaw down them and break out.
Its all up together now just a front leg to paint and a single pipe clamp needed.
Be interested in your rebuild probs and cures.