Well, I had the chances to play along a bit on the signature LD model in August 2003 during a jam on a private barbecue with Twins and Paul Leegan in Essen/Germany, and again in December 2004. It sounded ok. The things you hate, Roger, depend, of course, on individual taste.
Paul told us on various occasions that he received his one ( No.6 ) on the date of Lonnie´s last concert in October 2002 where he met Lon in the hotel as well as backstage later, and he was proud that Lonnie was first person ever played on this No.6 ( before Paul! ).
Paul played it on our recordings in August 2003 and in our Skiffle concerts in December 2004, too, and the guitar did a good job in this contexts. He recorded "Worried Man Blues" on it ( just vocals&guitar ) when we filmed an interview with Paul in a studio near Cologne for a Skiffle documentation on Dec 7, 2004, and it was great. So I can say only positive things about the sound as far as I know this model.

Regarding other guitar models I am definetly to young to say much about it. Of course, I know most of Lonnie´s recording by memory, but the guitar sounds there often depended on the mixing and of course on the style of playing, not only on the choice of model, so I do not want to make a final judgement about it. Others have better abilities and competence to do that.

But I guess Martin guitars have been principally a very good choice for all Skifflers, Blues and Folk Men, so I really like them.

I am not satisfied with the banjo Lonnie used on stage when I saw him live between 1996 and 2001, it sounded very "cheap". Maybe I had too much privileges to have always damned good banjos ( OME, Pietsch etc. ) in my own bands ( and have collaborated with excellent banjoplayers, too, like Peter"Banjo"Meyer, Sean Moyses, Udo Jägers etc. ). I like Lonnie´s banjo sound on most of the elder recordings of fifties, sixties and seventies, but was wondering about the "thin" sound of his banjo in recent years.