My Brilliant Career (or tall tales from a small mind)

I lost one arm on active duty (the Atlantis Campaign)
With the Swiss Coastguard,
So gave that up and put my hand, literally,
To becoming a bandit,
But I paid out too often.

So then I became a Corporal of industry,
But that was a false start.
And that was a false start.
Next I became a man of letters but
Could never figure out how a, e, i, o, u etc
Put food on the table.

I gave that up a year gone February thirtieth
And now I live on the shore of Loch Ness,
Painting portraits of the invisible man and
Carving non-returning boomerangs.
Things are looking up and tomorrow
Is the twelfth of maybe?