Thank you for the replies.
Upon further investigation the BUT sounds use a lot of the KIHA sounds, and hence the First Generation DMU Sounds look to be the best bet.
I am not looking to have the perfect SOUND or CabView folder, but I do want something that is more relevant.
In some instances it appears that I don't have much choice, such as using the DASH9 default sounds for the Class 67.
I shall continue to work up my COMMON.SOUND folder together with my COMMON.CAB folder. I have now started to rearrange my STOCK folders so that they more clearly relate to these, and hence should make the insertion of my revised SMS and CVF files easier.
I have to reinstall MSTS onto the VISTA laptop, at which time I will install Cambrian 2 plus add-on only. This will allow me to actually continue to drive trains, while I develop my TRAINS folder to suit the above process. The "fun" will start when I start to install the freeware routes and activities, and need to change the stock references, etc.
Oh well the ordered take-away should be here soon, and I will settle down for a quiet evening with my good lady wife.
All the best, Ruf

Working on exMT Thumper Project.