The tool to help get the clip over the rear spigot is the same as a Classic Mini and are available online for around a £5iver, if you don't want to pay inflated Morgan parts prices
Good tool, but the first time I used mine, I still managed to ruin the E clip!
Think when applying the spanners, I must have inadvertently loosened the centre bolt such that it introduced a very small gap between the cone face and the cylinder port. It was just enough to encourage the middle leg of the clip to get caught and it subsequently broke off!
Luckily, my supplier sent me a replacement clip f.o.c.
Having learnt from my mistake, all went well afterwards.