The white exhaust valve stem oil seals are a tight fit on the valve guides, even without the securing collar. They’re also a tight fit on the valve stems so it’s worth fitting the valves at this point before the springs.
The springs have caps at either end so, with a generous covering of oil, these sit over the valve stems.
The valves are attached to the springs via the collets. Like removal, this is a three handed job involving a heavy spring under compression so I didn’t take any photos. Essentially, with the spring compressed and some grease on the valve stems to hold the collets in place the spring can be slowly and carefully uncompressed until the spring cap rides up on the taper of the collets until the whole assembly is secure.
The biggest departure from the removal was the replacement of the “special” bolts used to to hold the lower end of the rocker pivot. As fitted by Citroën in their infinite wisdom the bolt has a strange head that has two flats. Whilst this came off with the assistance of an adjustable spanner I didn’t want to put it back so I used a 35mm M8 threaded hex headed bolt. This fits exactly as the original and uses a standard tool.
With the rockers fitted that’s the heads reassembled as far as possible.