You may have hit the nail on the head there Martin. I've had a look and seen nothing that touches the band you recommend in terms of size and repertoire.
Ignorance is bliss, bliss is happiness, I am happy...to draw your attention to the possible connectivity in the foregoing.
I would endorse the Railway Swing Band as we had them for a Hellfire Corner dance one year and they are very good.
It was unfortunate for them that in the previous years we had the Jeff Short Big Band, playing in true Glen Miller style USAAF uniforms and they were a very hard act to follow being one of the top such bands in the country. We had to bring them down from Essex and they were very, very expensive, hence the change.
As far as local bands are concerned though the RSB are top notch.