Metropolitan Police officer's medals

[NormanW]

This postcard photo has been found in an office drawer.  From the uniforms, duty arm bands, divisional letter on the helmet pates ,snake fastener belts, I believe they are Metropolitan Police.
The Acting Sgt on the front row, 3rd right, is wearing the three 1st World War medals, so date is 1919 or there after.

However many officers including the detective have a medal on a ring with an edge band and two central dark bands.  On some the medal is preceded aby another with a light central band.

The officer second left has the four banded medal succeeded by another which appears to have several clasps.

Could anyone suggest what these medals might be please?   This is the best quality scan I can get from the photo.

[bigjarofwasps]

44 minutes ago, NormanW said:

This postcard photo has been found in an office drawer.  From the uniforms, duty arm bands, divisional letter on the helmet pates ,snake fastener belts, I believe they are Metropolitan Police.
The Acting Sgt on the front row, 3rd right, is wearing the three 1st World War medals, so date is 1919 or there after.

However many officers including the detective have a medal on a ring with an edge band and two central dark bands.  On some the medal is preceded aby another with a light central band.

The officer second left has the four banded medal succeeded by another which appears to have several clasps.

Could anyone suggest what these medals might be please?   This is the best quality scan I can get from the photo.

Officer on the left , has the 1911 Coronation Medal and  I would suggest the Queens Boer War medal? 
 

Officer on the right 1902 Coronation Medal and 1911 Coronation Medal. 
 

 

Officer with WW1 medals and two stripes is interesting. Not seen that before.
But the officer three stripes and a crown I have seen before. 

 

 

Edited February 4 by bigjarofwasps

[NormanW]

Thank you.  Most useful.

The three stripes and crown was an actual rank of Station Sergeant.  Earlier the Met had four stripes for the rank.  Quite a number of forces had two stripes for an acting Sgt.