1944 GRI No.1 MKIII

[Bruce_in_Oz]

Looking at the third photo you posted; the one showing the underside of the bolt-head, maybe your gun-plumber meant "lip" not "clip". Unless the bolt-head is retained in the "groove" along the right side of the body, it will make closing the bolt difficult, to say the least. When you put the bolt in, does the bolt-head "clip" firmly over the little machined spring plate, (Spring, Retaining), just in front of the RH locking shoulder?

If the bolt-head is not fully engaged with this spring and thus, the guide groove forward of it, the extractor will foul the body and prevent bolt closure.

If the "Spring, retaining" is in good condition, but there is no positive "click" when you press the bolt-head down, the problem may be as simple as a loose retaining screw allowing the spring to flop about a bit. annoyingly, the fore-end has to be removed to tighten that screw. This will also entail the removal of the outer band (the front band with the sling swivel on it). This, in turn normally requires that the screw in that band must be removed. DO NOT just try to wind it out with the "big screwdriver" or you will mangle the threads in the band. On all original fittings, the end of the screw has a hollow end which is flared outwards with a punch, so that it stays in place. The trick is to CAREFULLY drill into the flared-out hollow end until it no longer binds on the thread in the band.They have a bastard, "Enfield special" thread (usually). Most purveyors of fine Lee Enfield parts will have these screws in stock because they were a "disposable" item, being removed EVERY time the fore-end was removed for examination or repairs. If and when you remove this screw, use a single, tiny drop of Loctite to retain the new one as it is correctly torqued up. (Hand-guard should not rattle, band should not move but the sling swivel should be free to move).

Options, then:

Damaged bolt-head; REPLACE, which is NOT as simple a task as might be imagined.

Broken or worn / distorted retaining spring: (replace),

Or a loose screw: (Tighten). That screw also doubles as the pivot for the sear, so it needs to be in good conditions and firmly snugged up in the correct place.