This tune is ‘mistitled’. It was composed by George Rowley(fiddler originally from Co.Meath) and Ned Stapleton(flute player - Dublin) in honour of their friend- accordeon player Sonny Brogan, who had emigrated to England in the 1950’s (probably) and returned sooner than expected. They had the tune ready in time for his return. ‘The Wanderer’s Return’ was a name Ned Stapleton himself had for it. Micheal O Raghallaigh(Concertina - Co.na Midhe) has it right in the slieve notes to his ‘Nervous Man’ CD - ‘Fair play’ to him!

But it is also known as “Sonny’s Return” and “Paddy Lynn’s Delight”. Paddy Lynn’s is not the original title, as you’ve pointed out, but there are many tunes with known composers which have many names attached to them.

Eg: Love at it’s Ending (composed by Ed Reavy) has also been known as the Head of Cabbage, however that came about.

I recorded this tune in 1965 on an album called “A Tribute to Michael Coleman “ which featured Andy McGann Felix Dolan and Myself. I have no idea now where I got the tune . When it came to listing the tracks there were a few tunes we could not find titles for. Paddy Lynn RIP was a bus driver in New York and a great lover of the music. He came from Co Mayo .The recording was done in” Broadway Recording Studio” on November 4 1965 and Paddy was with us to provide some support and refreshments. Someone suggested the title for this lovely tune and it is known as Paddy Lynn"s Delight ever since.  May Paddy and the good people who created the tune rest in peace.  Joe Burke.

Interested in the above tune “The Wanderer’s Return"as my grandfather was Sonny Brogan

Back in the summer of 1978 I had been invited to stay a few days at the house of Paddy O’Brien by his daughter Eileen. She was very gracious in inviting me to stay with her family when on tour with the Comhaltas North American concert tour of ‘77.
That summer I had never met a more generous and delightful human being than that of her father. Aside from accomodating me at their house for several days Paddy took me around his area and into a few exquisite sessions at the Old Barge Inn (or was it the New?).
He shared many a fascinating story about his own travels in New York and beyond.
I was an aspiring fiddler at the time (still am) and one night at a session Paddy asked me to play a tune. Needless to say I was quite nervous but flailed out a few reels to the best of my abilities. Paddy complimented me by informing that I had good taste in the reel selection, “I composed the 2nd tune and named it after a friend and postman in New York who’s own talent was to whistle reels and jigs beautifully. I call it the “The Whistling Postman”. “ Paddy told me.
My memory over the years sometimes makes a composite and mixes and matches other experiences together. So I may be inaccurate about the actual tune I had played for him and its name but for years I had thought Paddy had said that the postman’s name was Paddy Lynn and thus thought the tune “Paddy Lynn’s Delight” was his composition. Thanks to Joe Burke’s clarification on who Paddy Lynn was I realize I probably did not know “ Sonny’s Return” at the time but more than likely played the tune Paddy composed in Dm that is most commonly called “Dinny O’Brien’s” after his father. Is it possible there is even another tune of Paddy’s called “The Whistling Postman”?

Aodan is spot on (almost).  George Rowley was originally from Leitrim (relocated to Dublin), not Meath.  Also I think it was composed in the 40s, not the 50s (but I’m not 100% on that).

Interesting discussion on melodeon.net site about Sonny Brogan