Oh no, don't thank him. Now you know that the No1 MkIII exists, you need to get one.....and that's how it starts:madsmile:
Yep, the SMLE threads are the oddball Enfield form, whereas, IIRC, the No4 striker thread is 1/4" BSF (don't quote me I'm speaking from dodgy memory - they're different, anyway).
You can fit an SMLE firing pin and cocking piece to a No.4 bolt with no problem. The threads are different so it must be done as an assembly.