"a Scottish mother and an English Father, "
Ewan's father was from Falkirk (maybe that't moved to Oxfordshire!)
"one area where you take a different line from Ewan MacColl,"
How is that Dick (apart from the fact I disgreed with Ewan on many things while he was alive and we argued about them on several occasions - but you wouldn't be expected to know that?

Early in his career Ewan, like everyone in the revival, were singing in a 'Rainbow Nation' of accents - both Ewan and Bert indulged in the mid-Atlantic American ones occasionally
Alan Lomax appeared on the scene, took them all by the scruff of the neck and demanded to know why they weren't singing their own songs in their own accents - they began to do just that
MacColl was no different than kids from Irish families born in London - his accent was formed from what he heard at home and what he heard in the street - he was (according to a contemporary I once spoke to, Eddie Frow) a mixture of both, depending who he was with.
His parents spoke, their own dialects they had Scots neighbours and friends and they took in a series of Scots lodgers
I lived with Ewan Peggy and his mother, Betsy for a short time when I moved to London - when Ewan and his mother were in deep conversation his accent thickened to much you may as well have been sitting with a Bangladeshi mother and son at times.

Maccoll loved the Scots ballads - he was found singing them to a cinema queue in Manchester by a BBC employee during the Depression
From a report of his first being discovered in 1931.
Prospero and Ariel, G D Bridson.

"MacColl had been out busking for pennies by the Manchester theatres and cinemas. The songs he sang were unusual, Scots songs, Gaelic songs he had learnt from his mother, border ballads and folk-songs. One night while queueing up for the three-and-sixpennies, Kenneth Adam had heard him singing outside the Manchester Paramount. He was suitably impressed. Not only did he give MacColl a handout; he also advised him to go and audition for Archie Harding at the BBC studios in Manchester’s Piccadilly."

MacColl and Bert took it on themselves to popularise the ballads and made the groundbreaking 'Riverside' albums
Ewan's training as an actor taught him to utilise his familiarity with an accent he was well used to to make the ballads and Scots songs accessible to a British and American audience
In m opinion, it was far more genuine than most of the attempts at American accents you still hear in clubs today, which somehow never make it further west than The Isle of Man

I was brought up in a working class area of Liverpool with a broad local accent that everybody took the piss out of when I left home
I moved to Manchester and my accent changed, the same when I moved to London - now I live in the west of Ireland it's changed again - but it has never lot its earlier influences and it broadens when I phone home (I'll bet E.T's did too!)

Ewan always had a poor Irish accent when he used it - if he'd continued to do so it would have been a problem nowadays it's only an issue to people who want it to be
He had a not bad Liverpool accent when he sang sea songs in the early days - he never kept that up.
Jim Carroll