British Coachways was a consortium of Grey Green, Trathens, Parks of Hamilton, and Wallace Arnold Tours, who got together with Shearings/Pleasureways, Morris Brothers of Swansea, and Beeline of Middlesbrough to try and compete with National Express on routes into London from Scotland, the North and the West of England.
Driving for WA at the time, I drove these between tours on the Edinburgh/Abredeen leg of the London/Aberdeen service, and Birmingham/London. Popular with the clients who used them, they ended the short lived partnership in (I think) 1981 or 2. Trathens continued to operate an express service from the West Country to London, as did WA with their Yorkshire Pullman service, which included seat service, complimentary newspapers, and operated daily Bradford/Leeds to London - usually full and quite often with duplicates running.
In time the Plaxtons running these were replaced by Bova's painted in National Rapide livery, which operated for a couple of years more before WA withdrew from the agreement with National Express.
Other comments on this or amendmen.ts very welcome, but for more information try to get hold of the excellant "British Coachways - Ride the Flag", by Ken Bateman and Owen Woodliffe. Published by Rochester Press Transport Books ISBN 0946379 173