Early Dunlop brakes - replacing the seals

[iRS]

Does anyone have experience replacing the master cyclinder seals in the early Dunlop brakes system? This refers to 3.8L cars.
It seems the manual has a line missing. It refers to putting it back together but nothing about getting it apart.

Here's a photo of the internals and the new seals.

Here's the bit from the manual:

[iRS]

Just in case anyone finds this useful in the future, I figured out last night how to get it apart. There is a small tab under the spring to bend out slightly with a screwdriver. It simply comes apart after that and the seals can be changed easily.