WW1 - Military Medal identification

[Arcweld]

I have my great grandfather’s military medal but trying to identify and decipher the regiment and battalion to see if I can find anymore information or the reference to the dispatches. The rim of the medal has his serial number, rank (Pte) (assuming this is “Private”), his first initial and surname and then “3/L’pool. R.” From my limited research I gather this was the Kings Regiment (Liverpool) but any help to identify the battalion or any other information would be greatly appreciated. For example does the R at the end mean “reserve” or “Retired”?
Any other advice on how to find out more about the medal would be very much appreciated. Thanks