Ah-Ha,
I realise the problem that you may be having Greg.
The 45 single (that I have anyway) is Decca 45-F.10787 (DRF22318) and it's 'Dirty Old Town' by Alan Lomax and the Ramblers featuring (in lower case) Peggy Seeger and Ewan MacColl (probably one of the few times that Peggy's name came first).
On the other side 45-F.10787 (DRF22317) it's 'Hard Case' by Alan Lomax and the Ramblers featuring Ewan MacColl.
There's no date on the single but I suspect it was probably released about the same time as Feldman and Co. published 'The Skiffle Album' songbook 'featuring skiffle and folk songs popularised be Alan Lomax and the Ramlers' which was 1957.
Are you likely to be here in the IOM for this year's traditional boat festival? I can do you a copy.
Regrds.