The 4 pics of the OP's revolver show the standard Webley mfg's marking w/ MkII marking.
The second pic is a RSAF (Royal Small Arms Factory) inspectors marking.
I believe this one is from the Sparkbrook RSAF . They used the Block letter B in the marking(s),,Where Birmingham used the script letter B in their markings.
Sparkbrook Arsenal was closed around 1906 and it's workers and machinery, etc taken in by BSA.
Pic 3 is a standard Brit Military Proofing mark.
Crown/VR/crossed pennants
VR would Victoria Regina (Queen Victoria).
SHe died in 1901,,so that would be the latest this Webley would this military proof was applied.
The Crown style (Kings or Queens) would change with the Monarch on the Throne at the time as would the name below it in the 2 letter designation
ie: GR would be George Rex (King George),,etc)
The Broad Arrow mark is the standard British Armed Forces Property marking.
..and an other Inspectors mark for the bbl assembly. Block letter 'B'
The number is the individual inspector.
The back strap 'N' is a Royal Navy property marking.
Pretty plain,,but that's what they used both on rifles and handguns.
The '24' would likely be a Rack Number for the weapon.
The OP's revolver is not shaved.
The orig BroadArrow property marking is still in tact on the rear face of the cylinder. That would have been gone in a conversion. Plus simply look at the first pic/side view of the revolver and see how little space there is betw the rear of the cyl and the breech face.
That is all the room needed for the very thin .455 Webley cart rim,,and no more.
The fact that 45acp rds drop down in doesn't signify anything, They do that in a .455 chamber and that's why the 1/2moon clips are needed for use in the revolvers.
The 'shaved cyl' is also needed to use them so as to hold the 45acp rds from slipping down deep. Shaved for additional room for those moon clips.
You may be missing the top lever spring.