guitars were Bloody EVERYWHERE - even Poole!, by the late-50s

So they were - in the late 50s... But not necessarily so in the early 50s, particularly in the provinces. And almost certainly not in any folk scene.

Here are the No. 1 best record sellers of 1955:

Dickie Valentine - Finger Of Suspicion - 04/01/1955
Rosemary Clooney - Mambo Italiano - 11/01/1955
Dickie Valentine - Finger Of Suspicion (2nd time) - 18/01/1955
Rosemary Clooney - Mambo Italiano (2nd time) - 01/02/1955
Ruby Murray - Softly Softly - 15/02/1955
Tennessee Ernie Ford - Give Me Your Word - 08/03/1955
Perez Prado - Cherry Pink And Apple Blossom White - 26/04/1955
Tony Bennett - Stranger In Paradise - 10/05/1955
Eddie Calvert - Cherry Pink And Apple Blossom White - 24/05/1955
Jimmy Young - Unchained Melody - 21/06/1955
Alma Cogan - Dreamboat - 12/07/1955
Slim Whitman - Rose Marie - 26/07/1955
Jimmy Young - The Man From Laramie - 11/10/1955
Johnston Brothers - Hernando's Hideaway - 08/11/1955
Bill Haley and His Comets - Rock Around The Clock - 22/11/1955
Dickie Valentine - Christmas Alphabet - 13/12/1955

And here are the No. best selling singles of 1956:

Bill Haley and His Comets - Rock Around The Clock (2nd time) - 03/01/1956
Tennessee Ernie Ford - Sixteen Tons - 17/01/1956
Dean Martin - Memories Are Made Of This - 14/02/1956
Dreamweavers - It's Almost Tomorrow - 13/03/1956
Kay Starr - Rock And Roll Waltz - 27/03/1956
Dreamweavers - It's Almost Tomorrow (2nd time) - 03/04/1956
Winifred Atwell - Poor People Of Paris - 10/04/1956
Ronnie Hilton - No Other Love - 01/05/1956
Pat Boone - I'll Be Home - 12/06/1956
Frankie Lymon and The Teenagers - Why Do Fools Fall In Love - 17/07/1956
Doris Day - Whatever Will Be Will Be - 07/08/1956
Anne Shelton - Lay Down Your Arms - 18/09/1956
Frankie Laine - A Woman In Love - 16/10/1956
Johnnie Ray - Just Walkin' In The Rain - 13/11/1956

And here are the UK best sellers for 1957:

Guy Mitchell - Singing The Blues - 01/01/1957
Tommy Steele - Singing The Blues - 08/01/1957
Guy Mitchell - Singing The Blues (2nd time) - 15/01/1957
Frankie Vaughan - The Garden Of Eden - 22/01/1957
Guy Mitchell - Singing The Blues (3rd time) - 29/01/1957
Tab Hunter - Young Love - 19/02/1957
Lonnie Donegan - Cumberland Gap - 09/04/1957
Guy Mitchell - Rock A Billy - 14/05/1957
Andy Williams - Butterfly - 21/05/1957
Johnnie Ray - Yes Tonight Josephine - 04/06/1957
Lonnie Donegan - Gamblin' Man - 25/06/1957
Elvis Presley - All Shook Up - 09/07/1957
Paul Anka - Diana - 27/08/1957
The Crickets - That'll Be The Day - 29/10/1957
Harry Belafonte - Mary's Boy Child - 19/11/1957

A crude measure, I grant you but - even allowing for the innate conservatism of the established music industry of that period (beautifully chronicled by Pete Frame) - you can see that the influence of the guitar on music generally only really started in ernest in 1957. I admit it's only a pointer - but, in a general way, it shows that the rise of the guitar as a popular and established instrument only really kicked in in the mid-1950s at the earliest.