23rd Bn The London Regiment - Cap badge

[KurganFr]

Good day,

This is my first post on this forum; I hope you will excuse any inaccuracies.

I recently purchased - purely out of curiosity - the following cap badge (the images are quite small but hopefully clear enough):
http://i1195.photobucket.com/albums/...r/IMG_1565.jpg
http://i1195.photobucket.com/albums/...r/IMG_1566.jpg
http://i1195.photobucket.com/albums/...r/IMG_1567.jpg

I have a few questions that my untutored web searches have not yet answered:
1. Does this cap badge seem to be the genuine article?
2. What material(s) is it made of? Some websites make mention of bi-metal versions versus utility brass versions made during WWI. Would mine be a bi-metal, given that the star and arms are more silver in colour than the crown and parchment?
3. From http://www.queensroyalsurreys.org.uk...l/mvt45_1.html, it would seem that my cap badge would have been in use either between 1908-1914 or between 1920-1922. Would anybody be able to confirm this?
4. From what you can judge in the photos, what condition would you class it has, and do you know what it might be worth?

I would appreciate any assistance you may be able to provide.

Please let me know if different photos are required.

Thanks in advance.