Finding Relatives who served their country

Hello Everybody
Over the years I get many letters from various parts of the country asking for help tracing their relatives who served in the armed forces. It is no good asking if anyone knows my Uncle Tom who was in the Army and that’s all they have to go on. Therefore I have listed below what you need before asking for help and without most of these details you are completely wasting your time.
1 Full Name
2 Rank
3 Service Number
4 Regiment, Corps. Navy or Air force
5 Dates of service.
Quite a lot of the details above are on the rim of medals awarded.
Best wishes
Alan