Webley Service help

[deejayuu]

Difficult to be certain from photo but trajectory's thought looks spot on for me.

[Phil Russell]

If it won't press down, is the height of the latch wrong? If the barrel is locking but not pushing the latch down then maybe the latch needs building up so that the barrel pushes it down.
Or maybe I am missing the point.
Cheers, Phil

[Farsight]

It looks like a replacement to me: not quite the right shape. Is the spring lacking sufficient support within it's hole, and perhaps distorting enough to jam outside the sear, the part bearing on the receiver thereby becoming coil bound ?
The rifle appears to have had some "improvements" over the years

Atb,
Mark