It seems to be a variant of a WW1 Parody/Marching or Barrack Room song called Raining and Grousing. The verses and chorus can vary added to as fit.. and the use of bloody can be censored to a less coarse word. It's said to be a parody originating from 'Holy, Holy, Holy, Lord God Almighty'
                                    
It's Raining, raining, raining,
Always bloodywell raining.
Raining all the morning,
And raining all the night.

Lousing, lousing, lousing,
Always bloodywell lousing,
Lousing all the morning,
and lousing all the night.

Boozing, boozing, boozing,
Always bloodywell boozing,
Boozing all the morning,
and boozing all the night.

Grousing, grousing, grousing,
Always bloodywell grousing.
Grousing at the rations,
And grousing at the pay.

Marching, marching, marching,
Always bloodywell marching.
Marching dl the morning,
And marching al1 the night.
Marching, marching, marching,
Always bloodywell marching;
When the war is over
We'll damn well march no more